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E941 (Nitrogen)

E941 (Nitrogen)

CAS Number: 7727-37-9
EC Number: 231-783-9

E941 (Nitrogen) is the chemical element with the symbol N and atomic number 7. 
E941 (Nitrogen) is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. 
E941 (Nitrogen) is a common element in the universe, estimated at seventh in total abundance in the Milky Way and the Solar System. 


At standard temperature and pressure, two atoms of the element bind to form N2, a colorless and odorless diatomic gas. 
N2 forms about 78% of Earth's atmosphere, making E941 (Nitrogen) the most abundant uncombined element. 


E941 (Nitrogen) occurs in all organisms, primarily in amino acids (and thus proteins), in the nucleic acids (DNA and RNA) and in the energy transfer molecule adenosine triphosphate. 


The human body contains about 3% E941 (Nitrogen) by mass, the fourth most abundant element in the body after oxygen, carbon, and hydrogen. 
The E941 (Nitrogen) cycle describes the movement of the element from the air, into the biosphere and organic compounds, then back into the atmosphere.


Many industrially important compounds, such as ammonia, nitric acid, organic nitrates (propellants and explosives), and cyanides, contain E941 (Nitrogen). 
The extremely strong triple bond in elemental E941 (Nitrogen) (N≡N), the second strongest bond in any diatomic molecule after carbon monoxide (CO), dominates E941 (Nitrogen) chemistry. 


This causes difficulty for both organisms and industry in converting N2 into useful compounds, but at the same time it means that burning, exploding, or decomposing E941 (Nitrogen) compounds to form E941 (Nitrogen) gas releases large amounts of often useful energy. 


E941 (Nitrogen) was first discovered and isolated by Scottish physician Daniel Rutherford in 1772. 
Although Carl Wilhelm Scheele and Henry Cavendish had independently done so at about the same time, Rutherford is generally accorded the credit because his work was published first. 


The name nitrogène was suggested by French chemist Jean-Antoine-Claude Chaptal in 1790 when it was found that E941 (Nitrogen) was present in nitric acid and nitrates. 


Antoine Lavoisier suggested instead the name azote, from the Ancient Greek: ἀζωτικός "no life", as E941 (Nitrogen) is an asphyxiant gas; this name is used in several languages, including French, Italian, Russian, Romanian, Portuguese and Turkish, and appears in the English names of some E941 (Nitrogen) compounds such as hydrazine, azides and azo compounds.


The wheat sheaf symbol and lightning reflect the importance of E941 (Nitrogen) to living things. 
E941 (Nitrogen) is important for plant growth and can be ‘fixed’ by lightning or added to soils in fertilisers.
A colourless, odourless gas.


E941 (Nitrogen) makes up 78% of the air, by volume. 
E941 (Nitrogen) is obtained by the distillation of liquid air. 


Around 45 million tonnes are extracted each year. 
E941 (Nitrogen) is found, as compounds, in all living things and hence also in coal and other fossil fuels.


E941 (Nitrogen) in the form of ammonium chloride, NH4Cl, was known to the alchemists as sal ammonia. 
E941 (Nitrogen) was manufactured in Egypt by heating a mixture of dung, salt and urine. 
E941 (Nitrogen) gas itself was obtained in the 1760s by both Henry Cavendish and Joseph Priestley and they did this by removing the oxygen from air. 


They noted E941 (Nitrogen) extinguished a lighted candle and that a mouse breathing E941 (Nitrogen) would soon die. 
Neither man deduced that E941 (Nitrogen) was an element. 
The first person to suggest this was a young student Daniel Rutherford in his doctorate thesis of September 1772 at Edinburgh, Scotland.


E941 (Nitrogen) is a non-flammable air gas that forms 78% of the earth's atmosphere.
E941 (Nitrogen) is one of the primary nutrients critical for the survival of all living organisms. 
E941 (Nitrogen) is a necessary component of many biomolecules, including proteins, DNA, and chlorophyll. 


Although E941 (Nitrogen) is very abundant in the atmosphere as diE941 (Nitrogen) gas (N2), E941 (Nitrogen) is largely inaccessible in this form to most organisms, making E941 (Nitrogen) a scarce resource and often limiting primary productivity in many ecosystems. 
Only when E941 (Nitrogen) is converted from dinitrogen gas into ammonia (NH3) does E941 (Nitrogen) become available to primary producers, such as plants.


In addition to N2 and NH3, E941 (Nitrogen) exists in many different forms, including both inorganic (e.g., ammonia, nitrate) and organic (e.g., amino and nucleic acids) forms. 
Thus, E941 (Nitrogen) undergoes many different transformations in the ecosystem, changing from one form to another as organisms use it for growth and, in some cases, energy. 


The major transformations of E941 (Nitrogen) are E941 (Nitrogen) fixation, nitrification, denitrification, anammox, and ammonification. 
The transformation of E941 (Nitrogen) into E941 (Nitrogen)'s many oxidation states is key to productivity in the biosphere and is highly dependent on the activities of a diverse assemblage of microorganisms, such as bacteria, archaea, and fungi.


Since the mid-1900s, humans have been exerting an ever-increasing impact on the global E941 (Nitrogen) cycle. 
Human activities, such as making fertilizers and burning fossil fuels, have significantly altered the amount of fixed E941 (Nitrogen) in the Earth's ecosystems. 


In fact, some predict that by 2030, the amount of E941 (Nitrogen) fixed by human activities will exceed that fixed by microbial processes. 
Increases in available E941 (Nitrogen) can alter ecosystems by increasing primary productivity and impacting carbon storage. 
Because of the importance of E941 (Nitrogen) in all ecosystems and the significant impact from human activities, E941 (Nitrogen) and its transformations have received a great deal of attention from ecologists.


E941 (Nitrogen) is an element with atomic symbol N, atomic number 7, and atomic weight 14.01.
E941 (Nitrogen), refrigerated liquid (cryogenic liquid) appears as colorless odorless liquid. 
Nontoxic.
E941 (Nitrogen) is a common normally colourless, odourless, tasteless and mostly diatomic non-metal gas. 


E941 (Nitrogen) has five electrons in its outer shell, so it is trivalent in most compounds.
E941 (Nitrogen) constitutes 78 percent of Earth's atmosphere and is a constituent of all living tissues. 
E941 (Nitrogen) is an essential element for life, because E941 (Nitrogen) is a constituent of DNA and, as such, is part of the genetic code.


E941 (Nitrogen) molecules occur mainly in air. 
In water and soils E941 (Nitrogen) can be found in nitrates and nitrites. 
All of these substances are a part of the E941 (Nitrogen) cycle, and there are all interconnected.


Humans have changed natural nitrate and nitrite proportions radically, mainly due to the application of nitrate-containing manures. 
E941 (Nitrogen) is emitted extensively by industrial companies, increasing the nitrate and nitrite supplies in soil and water as a consequence of reactions that take place in the E941 (Nitrogen) cycle. 


Nitrate concentrations in drinking water will greatly increase due to this.
E941 (Nitrogen) (N), nonmetallic element of Group 15 [Va] of the periodic table. 
E941 (Nitrogen) is a colourless, odourless, tasteless gas that is the most plentiful element in Earth’s atmosphere and is a constituent of all living matter.


E941 (Nitrogen) forms many thousands of organic compounds. 
Most of the known varieties may be regarded as derived from ammonia, hydrogen cyanide, cyanogen, and nitrous or nitric acid. 
The amines, amino acids, and amides, for example, are derived from or closely related to ammonia. 


Nitroglycerin and nitrocellulose are esters of nitric acid. 
Nitro compounds are obtained from the reaction (called nitration) between nitric acid and an organic compound. 
Nitrites are derived from nitrous acid (HNO2). 


Nitroso compounds are obtained by the action of nitrous acid on an organic compound. 
Purines and alkaloids are heterocyclic compounds in which E941 (Nitrogen) replaces one or more carbon atoms.
E941 (Nitrogen) is a colourless, odourless gas, which condenses at −195.8 °C to a colourless, mobile liquid. 


The element exists as N2 molecules, represented as :N:::N:, for which the bond energy of 226 kilocalories per mole is exceeded only by that of carbon monoxide, 256 kilocalories per mole. 
Because of this high bond energy the activation energy for reaction of molecular E941 (Nitrogen) is usually very high, causing E941 (Nitrogen) to be relatively inert to most reagents under ordinary conditions. 


Furthermore, the high stability of the E941 (Nitrogen) molecule contributes significantly to the thermodynamic instability of many E941 (Nitrogen) compounds, in which the bonds, although reasonably strong, are far less so than those in molecular E941 (Nitrogen). 
For these reasons, elemental E941 (Nitrogen) appears to conceal quite effectively the truly reactive nature of its individual atoms.


A relatively recent and unexpected discovery is that E941 (Nitrogen) molecules are able to serve as ligands in complex coordination compounds. 
The observation that certain solutions of ruthenium complexes can absorb atmospheric E941 (Nitrogen) has led to hope that one day a simpler and better method of E941 (Nitrogen) fixation may be found.


An active form of E941 (Nitrogen), presumably containing free E941 (Nitrogen) atoms, can be created by passage of E941 (Nitrogen) gas at low pressure through a high-tension electrical discharge. 
E941 (Nitrogen) glows with a yellow light and is much more reactive than ordinary molecular E941 (Nitrogen), combining with atomic hydrogen and with sulfur, phosphorus, and various metals, and capable of decomposing nitric oxide, NO, to N2 and O2.


A E941 (Nitrogen) atom has the electronic structure represented by 1s22s22p3. 
The five outer shell electrons screen the nuclear charge quite poorly, with the result that the effective nuclear charge felt at the covalent radius distance is relatively high. 


Thus E941 (Nitrogen) atoms are relatively small in size and high in electronegativity, being intermediate between carbon and oxygen in both of these properties. 
The electronic configuration includes three half-filled outer orbitals, which give the atom the capacity to form three covalent bonds. 


The E941 (Nitrogen) atom should therefore be a very reactive species, combining with most other elements to form stable binary compounds, especially when the other element is sufficiently different in electronegativity to impart substantial polarity to the bonds. 

When the other element is lower in electronegativity than E941 (Nitrogen), the polarity gives partial negative charge to the E941 (Nitrogen) atom, making its lone-pair electrons available for coordination. 


When the other element is more electronegative, however, the resulting partial positive charge on E941 (Nitrogen) greatly limits the donor properties of the molecule. 


When the bond polarity is low (owing to the electronegativity of the other element being similar to that of E941 (Nitrogen)), multiple bonding is greatly favoured over single bonding. 


If disparity of atomic size prevents such multiple bonding, then the single bond that forms is likely to be relatively weak, and the compound is likely to be unstable with respect to the free elements. 
All of these bonding characteristics of E941 (Nitrogen) are observable in E941 (Nitrogen)'s general chemistry.


Often the percentage of E941 (Nitrogen) in gas mixtures can be determined by measuring the volume after all other components have been absorbed by chemical reagents. 
Decomposition of nitrates by sulfuric acid in the presence of mercury liberates nitric oxide, which can be measured as a gas. 


E941 (Nitrogen) is released from organic compounds when they are burned over copper oxide, and the free E941 (Nitrogen) can be measured as a gas after other combustion products have been absorbed. 


The well-known Kjeldahl method for determining the E941 (Nitrogen) content of organic compounds involves digestion of the compound with concentrated sulfuric acid (optionally containing mercury, or its oxide, and various salts, depending on the nature of the E941 (Nitrogen) compound). 


In this way, the E941 (Nitrogen) present is converted to ammonium sulfate. 
Addition of an excess of sodium hydroxide releases free ammonia, which is collected in standard acid; the amount of residual acid, which has not reacted with ammonia, is then determined by titration.


E941 (Nitrogen) is essential to life on Earth. 
E941 (Nitrogen) is a component of all proteins, and it can be found in all living systems. 
E941 (Nitrogen) compounds are present in organic materials, foods, fertilizers, explosives and poisons. 


Named after the Greek word nitron, for "native soda," and genes for "forming," E941 (Nitrogen) is the fifth most abundant element in the universe. 
E941 (Nitrogen) gas constitutes 78 percent of Earth's air, according to the Los Alamos National Laboratory. 
On the other hand, the atmosphere of Mars is only 2.6 percent E941 (Nitrogen). 


In E941 (Nitrogen)'s gas form, E941 (Nitrogen) is colorless, odorless and generally considered as inert. 
In E941 (Nitrogen)'s liquid form, E941 (Nitrogen) is also colorless and odorless, and looks similar to water, according to Los Alamos.


E941 (Nitrogen) is an essential element for all forms of life and is the structural component of amino acids from which animal and human tissues, enzymes, and many hormones are made. 
For plant growth, available (fixed) E941 (Nitrogen) is usually the limiting nutrient in natural systems. 


E941 (Nitrogen) chemistry and overall cycling in the global environment are quite complex due to the number of oxidation states. 
E941 (Nitrogen) itself has five valence electrons and can be found at oxidation states between −3 and +5. 
Thus, numerous species can form from chemical, biochemical, geochemical, and biogeochemical processes. 


The seventh element of the periodic table between carbon and oxygen is E941 (Nitrogen).
E941 (Nitrogen)’s an important part of amino acids.
Around eighty per cent of the Earth’s atmosphere comprises E941 (Nitrogen) gas.


E941 (Nitrogen) has no colour, mostly diatomic non-metal gas which is odourless and colourless in nature.
Since E941 (Nitrogen) has five electrons in its outer shell, most of its compounds are trivalent.
E941 (Nitrogen) is a constituent of all living tissues. 


Since E941 (Nitrogen) is a component of DNA and part of a genetic code, E941 (Nitrogen) is an essential element of life.
E941 (Nitrogen) is found in nitrates and nitrites in soil and water.
All these substances are part of the E941 (Nitrogen) cycle and interconnected. 


Industrial companies emit E941 (Nitrogen) extensively, increasing nitrite and nitrate content in the ground and water, being the consequence of reactions in the E941 (Nitrogen) cycle.
E941 (Nitrogen) is an essential nutrient for plant growth, development and reproduction. 


Despite E941 (Nitrogen) being one of the most abundant elements on earth, E941 (Nitrogen) deficiency is probably the most common nutritional problem affecting plants worldwide – E941 (Nitrogen) from the atmosphere and earth's crust is not directly available to plants.


E941 (Nitrogen) is atomic number 7, which means each E941 (Nitrogen) atom has 7 protons. 
E941 (Nitrogen)'s element symbol is N. 
E941 (Nitrogen) is odorless, tasteless, and colorless gas at room temperature and pressure. 


E941 (Nitrogen)'s atomic weight is 14.0067.
E941 (Nitrogen) gas (N2) makes up 78.1% of the volume of the Earth's air. 
E941 (Nitrogen)'s the most common uncombined (pure) element on Earth. 


E941 (Nitrogen)'s estimated to be the 5th or 7th most abundant element in the Solar System and Milky Way.
While the gas is common on Earth, E941 (Nitrogen)'s not so abundant on other planets. 
For example, E941 (Nitrogen) gas is found in the atmosphere of Mars at levels of about 2.6 percent.


E941 (Nitrogen) is a nonmetal. 
Like other elements in this group, E941 (Nitrogen) is a poor conductor of heat and electricity and lacks metallic luster in solid form.
E941 (Nitrogen) gas is relatively inert, but soil bacteria can 'fix' E941 (Nitrogen) into a form that plants and animals can use to make amino acids and proteins.


Ammonia (NH3) is the most important commercial compound of E941 (Nitrogen). 
E941 (Nitrogen) is produced by the Haber Process. Natural gas (methane, CH4) is reacted with steam to produce carbon dioxide and hydrogen gas (H2) in a two step process. 


Hydrogen gas and E941 (Nitrogen) gas reacted via the Haber Process to produce ammonia. 
This colorless gas with a pungent odor is easily liquefied (in fact, the liquid is used as a E941 (Nitrogen) fertilizer). 


Ammonia is also used in the production of urea, NH2CONH2, which is used as a fertilizer, used in the plastic industry, and used in the livestock industry as a feed supplement. 
Ammonia is often the starting compound for many other E941 (Nitrogen) compounds.


E941 (Nitrogen) is a diatomic gas which comprises 78 percent of the earth's atmosphere.
In addition to air, E941 (Nitrogen) is found in the protein matter of all life forms, in some natural gas-hydrocarbon deposits, and in many organic and inorganic compounds.

Nontoxic, only slightly soluble in water and most other liquids, poor conductor of heat and electricity, inert. 
However at high temperatures and pressures, E941 (Nitrogen) will combine with some reactive metals (such as lithium and magnesium) to form nitrides, as well as with some gaseous elements such as hydrogen and oxygen.


E941 (Nitrogen) gas (N2) makes up 78.1% of the Earth’s air, by volume. 
The atmosphere of Mars, by comparison, is only 2.6% E941 (Nitrogen). 
From an exhaustible source in our atmosphere, E941 (Nitrogen) gas can be obtained by liquefaction and fractional distillation. 

E941 (Nitrogen) is found in all living systems as part of the makeup of biological compounds.
The French chemist Antoine Laurent Lavoisier mistakenly named E941 (Nitrogen) azote, meaning without life. 
However, E941 (Nitrogen) compounds are found in foods, organic materials, fertilizers, poisons, and explosives. 


E941 (Nitrogen), as a gas is colorless, odorless, and generally considered an inert element. 
As a liquid (boiling point = minus 195.8°C), it is also colorless and odorless, and is similar in appearance to water. E941 (Nitrogen) gas can be prepared by heating a water solution of ammonium nitrite (NH4NO3).


E941 (Nitrogen) (pronounced /ˈnaɪtrədʒɨn/) is a chemical element that has the symbol N and atomic number 7 and atomic mass 14.00674 u. 
Elemental E941 (Nitrogen) is a colorless, odorless, tasteless and mostly inert diatomic gas at standard conditions, constituting 78% by volume of Earth's atmosphere.


Many industrially important compounds, such as ammonia, nitric acid, organic nitrates (propellants and explosives), and cyanides, contain E941 (Nitrogen). 
The extremely strong bond in elemental E941 (Nitrogen) dominates E941 (Nitrogen) chemistry, causing difficulty for both organisms and industry in converting the N2 into useful compounds, and releasing large amounts of energy when these compounds burn or decay back into E941 (Nitrogen) gas.


The element E941 (Nitrogen) was discovered by Daniel Rutherford, a Scottish physician, in 1772. 
E941 (Nitrogen) occurs in all living organisms. 
E941 (Nitrogen) is a constituent element of amino acids and thus of proteins, and of nucleic acids (DNA and RNA). 


E941 (Nitrogen) resides in the chemical structure of almost all neurotransmitters, and is a defining component of alkaloids, biological molecules produced by many organisms.
Naturally occurring nitrate (NO3) concentrations in lakes and streams are typically less than 4 mg/L, and the concentration of nitrite (NO2) is generally much lower. 


The concentration of ammonia (NH3) in natural waters is generally less than 0.1 mg/L.
E941 (Nitrogen), like phosphorus, is an important nutrient for plant growth. 
In rivers and lakes, E941 (Nitrogen) can be dissolved in the water, attached to particles floating in the water and found in the bodies of all living organisms.


Forms of E941 (Nitrogen) in freshwater systems include inorganic E941 (Nitrogen): 
nitrate (NO3), nitrite (NO2), ammonia (NH3) and ammonium (NH4). 


These inorganic forms of E941 (Nitrogen) are the most bioavailable, meaning they are most easily used and taken up by organisms that live in the water. 
Other forms of E941 (Nitrogen) include organic E941 (Nitrogen). 
Kjeldahl E941 (Nitrogen) includes ammonia, ammonium and organic E941 (Nitrogen) together.


E941 (Nitrogen) is a colorless, odorless, tasteless, diatomic and generally inert gas at standard temperature and pressure.
At atmospheric pressure, E941 (Nitrogen) is liquid between 63 K and 77 K.
Liquids colder than this are considerably more expensive to make than liquid E941 (Nitrogen) is.


In the natural world, the E941 (Nitrogen) cycle is of crucial importance to living organisms. 
E941 (Nitrogen) is taken from the atmosphere and converted to nitrates through lightning storms and E941 (Nitrogen) fixing bacteria. 
The nitrates fertilize plant growth where the E941 (Nitrogen) becomes bound in amino acids, DNA and proteins. 


E941 (Nitrogen) can then be eaten by animals. 
Eventually the E941 (Nitrogen) from the plants and animals returns to the soil and atmosphere and the cycle repeats.
E941 (Nitrogen) is a chemical element with an atomic number of 7 (it has seven protons in its nucleus). 


Molecular E941 (Nitrogen) (N2) is a very common chemical compound in which two E941 (Nitrogen) atoms are tightly bound together. 
Molecular E941 (Nitrogen) is a colorless, odorless, tasteless, and inert gas at normal temperatures and pressures.
About 78% of Earth's atmosphere is E941 (Nitrogen). 


The strong triple-bond between the atoms in molecular E941 (Nitrogen) makes this compound difficult to break apart, and thus nearly inert. 
E941 (Nitrogen) is one of the most important elements in the chemistry of living creatures. 
For example, E941 (Nitrogen) is part of amino acids, the building blocks of proteins. 


The E941 (Nitrogen) Cycle traces the path of E941 (Nitrogen), in many different chemical forms, through the environment and living organisms. 
Certain microbes can take gaseous E941 (Nitrogen) from the air and convert it to ammonia, making it available to plants and other organisms in a process called "E941 (Nitrogen) fixation".


E941 (Nitrogen) (N) is the 7th element on the periodic table. 
E941 (Nitrogen) is the fifth most abundant element in the universe, and E941 (Nitrogen) is also fairly common on Earth. 


E941 (Nitrogen) is a major component of the Earth's atmosphere - about 78% of the atmosphere is E941 (Nitrogen). 
Through a process of fractional distillation, E941 (Nitrogen) can be obtained from liquefied air.


PROPERTIES of E941 (Nitrogen):
-ATOMIC:
A E941 (Nitrogen) atom has seven electrons. 
In the ground state, they are arranged in the electron configuration 1s2 2s2 2p1x 2p1y 2p1z. 


E941 (Nitrogen), therefore, has five valence electrons in the 2s and 2p orbitals, three of which (the p-electrons) are unpaired. 
E941 (Nitrogen) has one of the highest electronegativities among the elements (3.04 on the Pauling scale), exceeded only by chlorine (3.16), oxygen (3.44), and fluorine (3.98). 
(The light noble gases, helium, neon, and argon, would presumably also be more electronegative, and in fact are on the Allen scale.) 


Following periodic trends, E941 (Nitrogen)'s single-bond covalent radius of 71 pm is smaller than those of boron (84 pm) and carbon (76 pm), while E941 (Nitrogen) is larger than those of oxygen (66 pm) and fluorine (57 pm). 
The nitride anion, N3−, is much larger at 146 pm, similar to that of the oxide (O2−: 140 pm) and fluoride (F−: 133 pm) anions. 


The first three ionisation energies of E941 (Nitrogen) are 1.402, 2.856, and 4.577 MJ·mol−1, and the sum of the fourth and fifth is 16.920 MJ·mol−1. 
Due to these very high figures, E941 (Nitrogen) has no simple cationic chemistry. 


The lack of radial nodes in the 2p subshell is directly responsible for many of the anomalous properties of the first row of the p-block, especially in E941 (Nitrogen), oxygen, and fluorine. 
The 2p subshell is very small and has a very similar radius to the 2s shell, facilitating orbital hybridisation. 


E941 (Nitrogen) also results in very large electrostatic forces of attraction between the nucleus and the valence electrons in the 2s and 2p shells, resulting in very high electronegativities. 


Hypervalency is almost unknown in the 2p elements for the same reason, because the high electronegativity makes it difficult for a small E941 (Nitrogen) atom to be a central atom in an electron-rich three-center four-electron bond since it would tend to attract the electrons strongly to itself. 


Thus, despite E941 (Nitrogen)'s position at the head of group 15 in the periodic table, E941 (Nitrogen)'s chemistry shows huge differences from that of its heavier congeners phosphorus, arsenic, antimony, and bismuth.
E941 (Nitrogen) may be usefully compared to its horizontal neighbours carbon and oxygen as well as its vertical neighbours in the pnictogen column, phosphorus, arsenic, antimony, and bismuth. 


Although each period 2 element from lithium to oxygen shows some similarities to the period 3 element in the next group (from magnesium to chlorine; these are known as diagonal relationships), their degree drops off abruptly past the boron–silicon pair. 


The similarities of E941 (Nitrogen) to sulfur are mostly limited to sulfur nitride ring compounds when both elements are the only ones present.
E941 (Nitrogen) does not share the proclivity of carbon for catenation. 


Like carbon, E941 (Nitrogen) tends to form ionic or metallic compounds with metals. 
E941 (Nitrogen) forms an extensive series of nitrides with carbon, including those with chain-, graphitic-, and fullerenic-like structures.


E941 (Nitrogen) resembles oxygen with E941 (Nitrogen)'s high electronegativity and concomitant capability for hydrogen bonding and the ability to form coordination complexes by donating its lone pairs of electrons. 
There are some parallels between the chemistry of ammonia NH3 and water H2O. 


For example, the capacity of both compounds to be protonated to give NH4+ and H3O+ or deprotonated to give NH2− and OH−, with all of these able to be isolated in solid compounds.
E941 (Nitrogen) shares with both its horizontal neighbours a preference for forming multiple bonds, typically with carbon, oxygen, or other E941 (Nitrogen) atoms, through pπ–pπ interactions. 


Thus, for example, E941 (Nitrogen) occurs as diatomic molecules and therefore has very much lower melting (−210 °C) and boiling points (−196 °C) than the rest of its group, as the N2 molecules are only held together by weak van der Waals interactions and there are very few electrons available to create significant instantaneous dipoles. 


This is not possible for its vertical neighbours; thus, the E941 (Nitrogen) oxides, nitrites, nitrates, nitro-, nitroso-, azo-, and diazo-compounds, azides, cyanates, thiocyanates, and imino-derivatives find no echo with phosphorus, arsenic, antimony, or bismuth. 


By the same token, however, the complexity of the phosphorus oxoacids finds no echo with E941 (Nitrogen). 
Setting aside their differences, E941 (Nitrogen) and phosphorus form an extensive series of compounds with one another; these have chain, ring, and cage structures.

ISOTOPES of E941 (Nitrogen):
E941 (Nitrogen) has two stable isotopes: 14N and 15N. 
The first is much more common, making up 99.634% of natural E941 (Nitrogen), and the second (which is slightly heavier) makes up the remaining 0.366%. 


This leads to an atomic weight of around 14.007 u. 
Both of these stable isotopes are produced in the CNO cycle in stars, but 14N is more common as E941 (Nitrogen)'s neutron capture is the rate-limiting step. 


14N is one of the five stable odd–odd nuclides (a nuclide having an odd number of protons and neutrons); the other four are 2H, 6Li, 10B, and 180mTa.
The relative abundance of 14N and 15N is practically constant in the atmosphere but can vary elsewhere, due to natural isotopic fractionation from biological redox reactions and the evaporation of natural ammonia or nitric acid. 


Biologically mediated reactions (e.g., assimilation, nitrification, and denitrification) strongly control E941 (Nitrogen) dynamics in the soil. 
These reactions typically result in 15N enrichment of the substrate and depletion of the product.


The heavy isotope 15N was first discovered by S. M. Naudé in 1929, and soon after heavy isotopes of the neighbouring elements oxygen and carbon were discovered. 
E941 (Nitrogen) presents one of the lowest thermal neutron capture cross-sections of all isotopes. 


E941 (Nitrogen) is frequently used in nuclear magnetic resonance (NMR) spectroscopy to determine the structures of E941 (Nitrogen)-containing molecules, due to E941 (Nitrogen)'s fractional nuclear spin of one-half, which offers advantages for NMR such as narrower line width. 


14N, though also theoretically usable, has an integer nuclear spin of one and thus has a quadrupole moment that leads to wider and less useful spectra. 


15N NMR nevertheless has complications not encountered in the more common 1H and 13C NMR spectroscopy. 
The low natural abundance of 15N (0.36%) significantly reduces sensitivity, a problem which is only exacerbated by its low gyromagnetic ratio, (only 10.14% that of 1H). 


As a result, the signal-to-noise ratio for 1H is about 300 times as much as that for 15N at the same magnetic field strength. 
This may be somewhat alleviated by isotopic enrichment of 15N by chemical exchange or fractional distillation. 


15N-enriched compounds have the advantage that under standard conditions, they do not undergo chemical exchange of their E941 (Nitrogen) atoms with atmospheric E941 (Nitrogen), unlike compounds with labelled hydrogen, carbon, and oxygen isotopes that must be kept away from the atmosphere. 


The 15N:14N ratio is commonly used in stable isotope analysis in the fields of geochemistry, hydrology, paleoclimatology and paleoceanography, where it is called δ15N.


Of the ten other isotopes produced synthetically, ranging from 12N to 23N, 13N has a half-life of ten minutes and the remaining isotopes have half-lives on the order of seconds (16N and 17N) or milliseconds. 
No other E941 (Nitrogen) isotopes are possible as they would fall outside the nuclear drip lines, leaking out a proton or neutron. 


Given the half-life difference, 13N is the most important E941 (Nitrogen) radioisotope, being relatively long-lived enough to use in positron emission tomography (PET), although its half-life is still short and thus E941 (Nitrogen) must be produced at the venue of the PET, for example in a cyclotron via proton bombardment of 16O producing 13N and an alpha particle.


The radioisotope 16N is the dominant radionuclide in the coolant of pressurised water reactors or boiling water reactors during normal operation. 
E941 (Nitrogen) is produced from 16O (in water) via an (n,p) reaction, in which the 16O atom captures a neutron and expels a proton. 
E941 (Nitrogen) has a short half-life of about 7.1 s, but during E941 (Nitrogen)'s decay back to 16O produces high-energy gamma radiation (5 to 7 MeV). 


Because of this, access to the primary coolant piping in a pressurised water reactor must be restricted during reactor power operation. 
E941 (Nitrogen) is a sensitive and immediate indicator of leaks from the primary coolant system to the secondary steam cycle, and is the primary means of detection for such leaks.


USES and APPLICATIONS of E941 (Nitrogen):
-Apart from E941 (Nitrogen)'s use in fertilisers and energy stores, E941 (Nitrogen) is a constituent of organic compounds as diverse as Kevlar used in high-strength fabric and cyanoacrylate used in superglue. 
-E941 (Nitrogen) is a constituent of every major pharmacological drug class, including antibiotics. 


-Many drugs are mimics or prodrugs of natural E941 (Nitrogen)-containing signal molecules: for example, the organic nitrates nitroglycerin and nitroprusside control blood pressure by metabolizing into nitric oxide. 
-Many notable E941 (Nitrogen)-containing drugs, such as the natural caffeine and morphine or the synthetic amphetamines, act on receptors of animal neurotransmitters.


-Gas:
The applications of E941 (Nitrogen) compounds are naturally extremely widely varied due to the huge size of this class: hence, only applications of pure E941 (Nitrogen) itself will be considered here. 
Two-thirds (2/3) of E941 (Nitrogen) produced by industry is sold as the gas and the remaining one-third (1/3) as the liquid.


-As a modified atmosphere, pure or mixed with carbon dioxide, to E941 (Nitrogen)ate and preserve the freshness of packaged or bulk foods (by delaying rancidity and other forms of oxidative damage). 
-Pure E941 (Nitrogen) as food additive is labeled in the European Union with the E number E941.


-In incandescent light bulbs as an inexpensive alternative to argon.
-In fire suppression systems for Information technology (IT) equipment.
-In the manufacture of stainless steel.


-In the case-hardening of steel by nitriding.
-In some aircraft fuel systems to reduce fire hazard (see inerting system).
-To inflate race car and aircraft tires, reducing the problems of inconsistent expansion and contraction caused by moisture and oxygen in natural air.


-Large amounts of ammonia are then used to create fertilizers, explosives and, through a process known as the Ostwald process, nitric acid (HNO3).
-E941 (Nitrogen) gas is largely inert and is used as a protective shield in the semiconductor industry and during certain types of welding and soldering operations. 


-However, the liquid E941 (Nitrogen) is used to produce fog in cocktails.
-Oil companies use high pressure E941 (Nitrogen) to help force crude oil to the surface.
-Liquid E941 (Nitrogen) is an inexpensive cryogenic liquid used for refrigeration, preservation of biological samples and for low temperature scientific experimentation. 


-E941 (Nitrogen) gas is used as a nonflammable protective atmosphere. 
-The liquid form of the element is used to remove warts, as a computer coolant, and for cryogenics. 
-E941 (Nitrogen) is commonly used during sample preparation in chemical analysis. 


-E941 (Nitrogen) is used to concentrate and reduce the volume of liquid samples. 
-Directing a pressurised stream of E941 (Nitrogen) gas perpendicular to the surface of the liquid causes the solvent to evaporate while leaving the solute(s) and un-evaporated solvent behind.


-E941 (Nitrogen) can be used as a replacement, or in combination with, carbon dioxide to pressurise kegs of some beers, particularly stouts and British ales, due to the smaller bubbles it produces, which makes the dispensed beer smoother and headier. 
-A pressure-sensitive E941 (Nitrogen) capsule known commonly as a "widget" allows E941 (Nitrogen)-charged beers to be packaged in cans and bottles.


-E941 (Nitrogen) is part of many important compounds, such as nitrous oxide, nitroglycerin, nitric acid, and ammonia. 
The triple bond E941 (Nitrogen) forms with other E941 (Nitrogen) atoms is extremely strong and releases considerable energy when broken, which is why is so valuable in explosives and also "strong" materials such as Kevlar and cyanoacrylate glue ("super glue").


-E941 (Nitrogen) tanks are also replacing carbon dioxide as the main power source for paintball guns. 
-E941 (Nitrogen) must be kept at higher pressure than CO2, making N2 tanks heavier and more expensive.


-Equipment:
Some construction equipment uses pressurized E941 (Nitrogen) gas to help hydraulic system to provide extra power to devices such as hydraulic hammer. 
E941 (Nitrogen) gas, formed from the decomposition of sodium azide, is used for the inflation of airbags.


-Liquid:
Liquid E941 (Nitrogen) is a cryogenic liquid which looks like water. 
When insulated in proper containers such as dewar flasks, E941 (Nitrogen) can be transported and stored with a low rate of evaporative loss.


-Like dry ice, the main use of liquid E941 (Nitrogen) is for cooling to low temperatures. 
E941 (Nitrogen) is used in the cryopreservation of biological materials such as blood and reproductive cells (sperm and eggs). 
-E941 (Nitrogen) is used in cryotherapy to remove cysts and warts on the skin by freezing them.


-E941 (Nitrogen) is used in laboratory cold traps, and in cryopumps to obtain lower pressures in vacuum pumped systems. 
-E941 (Nitrogen) is used to cool heat-sensitive electronics such as infrared detectors and X-ray detectors. 


-Other uses include freeze-grinding and machining materials that are soft or rubbery at room temperature, shrink-fitting and assembling engineering components, and more generally to attain very low temperatures where necessary. 


-Because of E941 (Nitrogen)'s low cost, liquid E941 (Nitrogen) is often used for cooling even when such low temperatures are not strictly necessary, such as refrigeration of food, freeze-branding livestock, freezing pipes to halt flow when valves are not present, and consolidating unstable soil by freezing whenever excavation is going on underneath.


-E941 (Nitrogen) is important to the chemical industry. 
E941 (Nitrogen) is used to make fertilisers, nitric acid, nylon, dyes and explosives. 
To make these products, E941 (Nitrogen) must first be reacted with hydrogen to produce ammonia. 

This is done by the Haber process. 
150 million tonnes of ammonia are produced in this way every year.


-E941 (Nitrogen) gas is also used to provide an unreactive atmosphere. 
E941 (Nitrogen) is used in this way to preserve foods, and in the electronics industry during the production of transistors and diodes. 


-Large quantities of E941 (Nitrogen) are used in annealing stainless steel and other steel mill products. 
Annealing is a heat treatment that makes steel easier to work.
-Liquid E941 (Nitrogen) is often used as a refrigerant. 


-E941 (Nitrogen) is used for storing sperm, eggs and other cells for medical research and reproductive technology. 
-E941 (Nitrogen) is also used to rapidly freeze foods, helping them to maintain moisture, colour, flavour and texture.
-E941 (Nitrogen) is not reactive and E941 (Nitrogen) is excellent for blanketing and is often used as purging gas. 


-E941 (Nitrogen) can be used to remove contaminants from process streams through methods such as stripping and sparging. 
-Due to E941 (Nitrogen)'s properties it can be used for protection of valuable products against harmful contaminants. 
-E941 (Nitrogen) also enables safe storage, usage of flammable compounds and can help prevent combustible dust explosions.


-Two-thirds of E941 (Nitrogen) produced by industry is sold as the gas and the remaining one-third as the liquid. 
-E941 (Nitrogen), The gas is mostly used as an inert atmosphere whenever the oxygen in the air would pose a fire, explosion, or oxidising hazard. 


-Food industry:
E941 (Nitrogen) gas is also used to provide an unreactive atmosphere. 
E941 (Nitrogen) is used in this way to preserve foods. 

As a modified atmosphere, pure or mixed with carbon dioxide, to E941 (Nitrogen)ate and preserve the freshness of packaged or bulk foods (by delaying rancidity and other forms of oxidative damage like changing colours). 
Pure E941 (Nitrogen) as food additive is labelled in the European Union with the E number E941.


-Light bulbs industry:
Bulbs should not be filled with air since hot tungsten wire will combust in presence of oxygen. 
You can’t maintain vacuum either or external atmospheric pressure will break the glass. 

So, they must be filled with non-reactive gas like E941 (Nitrogen). 
We can use inert gases like argon or helium instead of E941 (Nitrogen), but they are more expensive & rarer than E941 (Nitrogen). 


-Fire suppression systems:
Fire suppression is achieved by reducing the oxygen concentration where the fire will extinguish, while remaining at a level acceptable for human exposure for a short period of time.


-Stainless steel manufacturing:
There are various instances when E941 (Nitrogen) can be added to steel during steelmaking such as melting, the ladle processing and the casting operations. 
E941 (Nitrogen) effect on hardness, formability, strain ageing and impact properties.


-Chemical analysis and chemical industry:
E941 (Nitrogen) is commonly used during sample preparation in chemical analysis. 
E941 (Nitrogen) is used to concentrate and reduce the volume of liquid samples.

E941 (Nitrogen) is also important to the chemical industry. 
E941 (Nitrogen)is used in production of fertilisers, nitric acid, nylon, dyes and explosives.


-Pressurised beer kegs:
E941 (Nitrogen) can be used as a replacement, or in combination with, carbon dioxide to pressurise kegs of some beers, particularly stouts and British ales, due to the smaller bubbles it produces, which makes the dispensed beer smoother and headier. E941 (Nitrogen)-charged beers can be packaged in cans and bottles.


-Tire filling systems
E941 (Nitrogen) is used to inflate race car and aircraft tires, reducing the problems caused by moisture and oxygen in natural air. E941 (Nitrogen) is less likely to migrate through tire rubber than oxygen, which means that your tire pressures will remain more stable over the long term. 
That means more consistent inflation pressures during a use as the tires heat up.


-Aircraft fuel systems
In some aircraft fuel systems E941 (Nitrogen) is used to reduce fire hazard. 


-Biological role:
E941 (Nitrogen) is cycled naturally by living organisms through the ‘E941 (Nitrogen) cycle’. 
E941 (Nitrogen) is taken up by green plants and algae as nitrates, and used to build up the bases needed to construct DNA, RNA and all amino acids. 
Amino acids are the building blocks of proteins.


-Used to freeze foods, to preserve whole blood and other biologicals, and as a coolant.
-Animals obtain their E941 (Nitrogen) by consuming other living things. 
They digest the proteins and DNA into their constituent bases and amino acids, reforming them for their own use.


-Microbes in the soil convert the E941 (Nitrogen) compounds back to nitrates for the plants to re-use. 
The nitrate supply is also replenished by E941 (Nitrogen)-fixing bacteria that ‘fix’ E941 (Nitrogen) directly from the atmosphere.
-E941 (Nitrogen) is used to produce ammonia (Haber process) and fertilizers, vital for current food production methods. 


-E941 (Nitrogen) is also used to manufacture nitric acid (Ostwald process).
-In enhanced oil recovery, high pressure E941 (Nitrogen) is used to force crude oil that would otherwise not be recovered out of oil wells. 


-E941 (Nitrogen)’s inert qualities find use in the chemical and petroleum industries to blanket storage tanks with an inert layer of gas.
-Liquid E941 (Nitrogen) is used as a refrigerant. 


-Superconductors for practical technologies should ideally have no electrical resistance at temperatures higher than 63 K because this temperature is achievable relatively cheaply using liquid E941 (Nitrogen). 
Lower temperatures come with a much higher price tag.


-While elemental E941 (Nitrogen) is not very reactive, many of E941 (Nitrogen)’s compounds are unstable. 
Oxides naturally form in steel during welding and these weaken the weld. 
E941 (Nitrogen) can be used to exclude oxygen during welding, resulting in better welds.


-The inert gas is used in a variety of applications including cutting, purging, cooling and freezing.
-Valued for E941 (Nitrogen)'s inert properties in E941 (Nitrogen)'s gaseous form, E941 (Nitrogen) displaces air and therefore, reduces or eliminates the oxidation of materials. 


-E941 (Nitrogen) is also used as an assist gas for laser cutting. 
-Given the extremely low temperatures of its liquid state, E941 (Nitrogen) is an ideal gas for cryogenic cooling and freezing.
-E941 (Nitrogen) can be used in virtually any industry to improve yields and optimize performance. 


-E941 (Nitrogen) enables the safe storage and use of flammables and prevents the explosion of combustibles. 
-In addition, E941 (Nitrogen) improves the quality and shelf-life of air-sensitive materials such as food, pharmaceuticals and electronic products.


-The greatest single commercial use of E941 (Nitrogen) is as a component in the manufacture of ammonia, subsequently used as fertilizer and to produce nitric acid.
-Liquid E941 (Nitrogen) (often referred to as LN2) is used as a refrigerant for freezing and transporting food products, for the preservation of bodies and reproductive cells (sperm and eggs), and for stable storage of biological samples.


-Nitric acid salts include some important compounds, for example potassium nitrate, nitric acid, and ammonium nitrate. 
-Elemental E941 (Nitrogen) can be used as an inert atmosphere for reactions requiring the exclusion of oxygen and moisture. 


-In the liquid state, E941 (Nitrogen) has valuable cryogenic applications; except for the gases hydrogen, methane, carbon monoxide, fluorine, and oxygen, practically all chemical substances have negligible vapour pressures at the boiling point of E941 (Nitrogen) and exist, therefore, as crystalline solids at that temperature.


-In the chemical industry, E941 (Nitrogen) is used as a preventive of oxidation or other deterioration of a product, as an inert diluent of a reactive gas, as a carrier to remove heat or chemicals and as an inhibitor of fire or explosions. 


-In the food industry E941 (Nitrogen) gas is employed to prevent spoilage through oxidation, mold, or insects, and liquid E941 (Nitrogen) is used for freeze drying and for refrigeration systems. 


-In the electrical industry E941 (Nitrogen) is used to prevent oxidation and other chemical reactions, to pressurize cable jackets, and to shield motors. 
-E941 (Nitrogen) finds application in the metals industry in welding, soldering, and brazing, where it helps prevent oxidation, carburization, and decarburization. 


-As a nonreactive gas, E941 (Nitrogen) is employed to make foamed—or expanded—rubber, plastics, and elastomers, to serve as a propellant gas for aerosol cans, and to pressurize liquid propellants for reaction jets. 


-In medicine rapid freezing with liquid E941 (Nitrogen) may be used to preserve blood, bone marrow, tissue, bacteria, and semen.
-Liquid E941 (Nitrogen) has also proven useful in cryogenic research.


-Large quantities of E941 (Nitrogen) are used together with hydrogen to produce ammonia, NH3, a colourless gas with a pungent, irritating odour. 
-The chief commercial method of synthesizing ammonia is the Haber-Bosch process. 


-Ammonia is one of the two principal E941 (Nitrogen) compounds of commerce; it has numerous uses in the manufacture of other important E941 (Nitrogen) compounds. 
A large portion of commercially synthesized ammonia is converted into nitric acid (HNO3) and nitrates, which are the salts and esters of nitric acid. 

Ammonia is used in the ammonia-soda process (Solvay process) to produce soda ash, Na2CO3. 
Ammonia is also used in the preparation of hydrazine, N2H4, a colourless liquid used as a rocket fuel and in many industrial processes.


-Nitric acid is another popular commercial compound of E941 (Nitrogen). 
A colourless, highly corrosive liquid, it is much used in the production of fertilizers, dyes, drugs, and explosives. 


-Urea (CH4N2O) is the most common source of E941 (Nitrogen) in fertilizers. 
Ammonium nitrate (NH4NO3), a salt of ammonia and nitric acid, is also used as a E941 (Nitrogen)ous component of artificial fertilizers and, combined with fuel oil, as an explosive (ANFO).


-Nitrous oxide, also known as laughing gas, is sometimes used as an anesthetic; when inhaled it produces mild hysteria. Nitric oxide reacts rapidly with oxygen to form brown E941 (Nitrogen) dioxide, an intermediate in the manufacture of nitric acid and a powerful oxidizing agent utilized in chemical processes and rocket fuels.


-Also of some importance are certain nitrides, solids formed by direct combination of metals with E941 (Nitrogen), usually at elevated temperatures. 
They include hardening agents produced when alloy steels are heated in an atmosphere of ammonia, a process called nitriding. 

Those of boron, titanium, zirconium, and tantalum have special applications. 
One crystalline form of boron nitride (BN), for example, is nearly as hard as diamond and less easily oxidized and so is useful as a high-temperature abrasive.


-Azides, which may be either inorganic or organic, are compounds that contain three E941 (Nitrogen) atoms as a group, represented as (―N3). 
Most azides are unstable and highly sensitive to shock. 

Some of them, such as lead azide, Pb(N3)2, are used in detonators and percussion caps. 
The azides, like the halogen compounds, readily react with other substances by displacement of the so-called azide group and yield many kinds of compounds.


-In fact, about 80 percent of ammonia that is produced is used as fertilizer. 
-E941 (Nitrogen) is also used as a refrigerant gas; in the manufacture of plastics, textiles, pesticides and dyes; and in cleaning solutions, according to the New York Department of State.


-E941 (Nitrogen) is used in the manufacture of ammonia, to produce nitric acid and subsequently used as a fertilizer.
-Nitric acid salts include important compounds like potassium nitrate, ammonium nitrate, and nitric acid. 
Nitrated organic compounds such as nitro glycerine are often explosives.


-Liquid E941 (Nitrogen) is utilized as a refrigerant for transporting foodstuff and freezing purposes. 
Preservation of bodies and reproductive cells and stable storage of biological samples also makes use of liquid E941 (Nitrogen).
-E941 (Nitrogen) is used in almost all pharmacological drugs, and is found in nitrous oxide - an anesthetic. 


-E941 (Nitrogen) is used in a variety of ways in both its gaseous and liquid form, however E941 (Nitrogen) is also a major component of the group of pollutants known collectively as E941 (Nitrogen) oxides or NOx.
-E941 (Nitrogen) gas can be used to manufacture ammonia (NH3), which is used extensively to produce chemical fertilizers.


-As well, liquid E941 (Nitrogen) is available as a relatively inexpensive cryogenic liquid used to preserve biological specimen and conduct low temperature scientific experiments.
-As well, another major use of E941 (Nitrogen) is in the production of ammonia (NH3) in a process known as the Haber process. 
This ammonia is then used to create fertilizers, explosives, and nitric acid.


-Finally, E941 (Nitrogen) gas is inert (meaning that it is hard to make E941 (Nitrogen) have a chemical reaction) and thus E941 (Nitrogen) is used to create an atmosphere that prevents chemical reactions when producing semiconductors, as well as in some welding and soldering operations.


-Chemistry labs will also use E941 (Nitrogen) gas to prevent chemical reactions with the oxygen in the atmosphere.
-E941 (Nitrogen) makes up 78 per cent of the Earth’s atmosphere and is a part of all living tissue. 
E941 (Nitrogen) is a crucial ingredient of life since E941 (Nitrogen) is a constituent of DNA and as such is part of the genetic code.


-E941 (Nitrogen) molecules often exist in the soil. 
E941 (Nitrogen) can be present in nitrates and nitrites in water and in soil. 
These compounds are all part of the E941 (Nitrogen) cycle and both are interconnected.


-E941 (Nitrogen) is used as an effective way to prevent oxidation and provides a safe, inert atmosphere which “sweeps” off furnace-generated gases. 
-This is also used as a laser cutting assist steam, that facilitates plasma cutting. 


-Oil companies also use high pressure E941 (Nitrogen) to force crude oil out from the ground. 
-E941 (Nitrogen) is used in a broad variety of applications for upstream and midstream electricity.


WHERE IS E941 (Nitrogen) FOUND?
E941 (Nitrogen) is the fifth most abundant element in the universe, making up about 78 per cent of the atmosphere on earth, and contains an estimated 4,000 trillion tons of gas. 
E941 (Nitrogen) is extracted through a process called fractional distillation from liquefied air.


HOW DO YOU FIX E941 (Nitrogen)?
A wide range of microorganisms called diazotrophs, including bacteria such as azotobacter, and archaea, naturally conduct E941 (Nitrogen) fixation in the soil. 
Some E941 (Nitrogen)-fixing bacteria, particularly legumes, have symbiotic relationships with certain plant groups.


WHAT WOULD HAPPEN IF E941 (Nitrogen)-FIXING BACTERIA DID NOT EXIST? 
Bacteria transform airborne E941 (Nitrogen) and carbon dioxide into functional components that can be used as basic building blocks by plants and animals. 
To living organisms, a loss of all microbes would be terrible news that they can not produce or receive such essential nutrients on their own.


HOW DO PLANTS TAKE UP E941 (Nitrogen)?
In the form of nitrate (NO3−) and ammonium (NH4+), plants absorb E941 (Nitrogen) from the soil. 
Nitrate is typically the predominant type of absorbed E941 (Nitrogen) available in aerobic soils where nitrification can occur.

E941 (Nitrogen) is a key component of the bodies of living organisms. 
E941 (Nitrogen) atoms are found in all proteins. 
In E941 (Nitrogen) fixation, bacteria convert into ammonia, a form of E941 (Nitrogen) usable by plants. 

When animals eat the plants, they acquire usable E941 (Nitrogen) compounds.
E941 (Nitrogen) is everywhere! In fact, gas makes up about 78% of Earth's atmosphere by volume, far surpassing the  we often think of as "air".

But having E941 (Nitrogen) around and being able to make use of it are two different things. 
Your body, and the bodies of other plants and animals, have no good way to convert  into a usable form. 
We animals—and our plant compatriots—just don't have the right enzymes to capture, or fix, atmospheric E941 (Nitrogen).


WHERE DOES THAT E941 (Nitrogen) COME FROM? 
In the natural world, E941 (Nitrogen) comes from bacteria!
Bacteria play a key role in the E941 (Nitrogen) cycle.

E941 (Nitrogen) enters the living world by way of bacteria and other single-celled prokaryotes, which convert atmospheric E941 (Nitrogen) into biologically usable forms in a process called E941 (Nitrogen) fixation. 

Some species of E941 (Nitrogen)-fixing bacteria are free-living in soil or water, while others are beneficial symbionts that live inside of plants.

E941 (Nitrogen)-fixing microorganisms capture atmospheric E941 (Nitrogen) by converting E941 (Nitrogen) to ammonia which can be taken up by plants and used to make organic molecules. 
The E941 (Nitrogen)-containing molecules are passed to animals when the plants are eaten. 

They may be incorporated into the animal's body or broken down and excreted as waste, such as the urea found in urine.
E941 (Nitrogen) doesn't remain forever in the bodies of living organisms. 
Instead, E941 (Nitrogen)'s converted from organic E941 (Nitrogen) back into gas by bacteria. 

This process often involves several steps in terrestrial—land—ecosystems. 
E941 (Nitrogen)ous compounds from dead organisms or wastes are converted into ammonia by bacteria, and the ammonia is converted into nitrites and nitrates. 
In the end, the nitrates are made into gas by denitrifying prokaryotes.

E941 (Nitrogen) cycling in marine ecosystems:
So far, we’ve focused on the natural E941 (Nitrogen) cycle as it occurs in terrestrial ecosystems. 

However, generally similar steps occur in the marine E941 (Nitrogen) cycle. 
There, the ammonification, nitrification, and denitrification processes are performed by marine bacteria and archaea.

Some E941 (Nitrogen)-containing compounds fall to the ocean floor as sediment. 
Over long periods of time, the sediments get compressed and form sedimentary rock. 
Eventually, geological uplift may move the sedimentary rock to land. 


In the past, scientists did not think that this E941 (Nitrogen)-rich sedimentary rock was an important E941 (Nitrogen) source for terrestrial ecosystems. 
However, a new study suggests that it may actually be quite important—the E941 (Nitrogen) is released gradually to plants as the rock wears away, or weathers.

E941 (Nitrogen) as a limiting nutrient:
In natural ecosystems, many processes, such as primary production and decomposition, are limited by the available supply of E941 (Nitrogen). 
In other words, E941 (Nitrogen) is often the limiting nutrient, the nutrient that's in shortest supply and thus limits the growth of organisms or populations.


WHAT IS THE E941 (Nitrogen) CYCLE AND WHY IS IT KEY TO LIFE?
E941 (Nitrogen), the most abundant element in our atmosphere, is crucial to life. 
E941 (Nitrogen) is found in soils and plants, in the water we drink, and in the air we breathe. 

E941 (Nitrogen) is also essential to life: a key building block of DNA, which determines our genetics, is essential to plant growth, and therefore necessary for the food we grow. 
But as with everything, balance is key: too little E941 (Nitrogen) and plants cannot thrive, leading to low crop yields. 

Plants that do not have enough E941 (Nitrogen) become yellowish and do not grow well and can have smaller flowers and fruits. 
Understanding the E941 (Nitrogen) Cycle—how E941 (Nitrogen) moves from the atmosphere to earth, through soils and back to the atmosphere in an endless Cycle—can help us grow healthy crops and protect our environment.


WHY IS E941 (Nitrogen) IMPORTANT?
The delicate balance of substances that is important for maintaining life is an important area of research, and the balance of E941 (Nitrogen) in the environment is no exception. 
When plants lack E941 (Nitrogen), they become yellowed, with stunted growth, and produce smaller fruits and flowers. 

Farmers may add fertilizers containing E941 (Nitrogen) to their crops, to increase crop growth. 
Without E941 (Nitrogen) fertilizers, scientists estimate that we would lose up to one third of the crops we rely on for food and other types of agriculture. 


E941 (Nitrogen) IS KEY TO LIFE!
E941 (Nitrogen) is a key element in the nucleic acids.

DNA Deoxyribonucleic acid, a self-replicating material which is present in nearly all living organisms as the main component of chromosomes, and carrier of genetic information.

RNA Ribonucleic acid, a nucleic acid present in all living cells, acts as a messenger carrying instructions from DNA which are the most important of all biological molecules and crucial for all living things. 
DNA carries the genetic information, which means the instructions for how to make up a life form. 

When plants do not get enough E941 (Nitrogen), they are unable to produce amino acids (substances that contain E941 (Nitrogen) and hydrogen and make up many of living cells, muscles and tissue). 

Without amino acids, plants cannot make the special proteins that the plant cells need to grow. 
Without enough E941 (Nitrogen), plant growth is affected negatively. 


WHAT EXACTLY IS THE E941 (Nitrogen) CYCLE?
The E941 (Nitrogen) cycle is a repeating cycle of processes during which E941 (Nitrogen) moves through both living and non-living things: the atmosphere, soil, water, plants, animals and bacteria.

Microscopic living organisms that usually contain only one cell and are found everywhere. 
Bacteria can cause decomposition or breaking down, of organic material in soils.
In order to move through the different parts of the cycle, E941 (Nitrogen) must change forms. 

In the atmosphere, E941 (Nitrogen) exists as a gas (N2), but in the soils it exists as E941 (Nitrogen) oxide, NO, and E941 (Nitrogen) dioxide, NO2, and when used as a fertilizer, can be found in other forms, such as ammonia, NH3, which can be processed even further into a different fertilizer, ammonium nitrate, or NH4NO3.

There are five stages in the E941 (Nitrogen) cycle, and we will now discuss each of them in turn: fixation or volatilization, mineralization, nitrification, immobilization, and denitrification. 

In this image, microbes in the soil turn E941 (Nitrogen) gas (N2) into what is called volatile ammonia (NH3), so the fixation process is called volatilization. 

Leaching: 
When a mineral or chemical (such as nitrate, or NO3) drains away from soil or other ground material and leaks into surrounding area is where certain forms of E941 (Nitrogen) (such as nitrate, or NO3) becomes dissolved in water.

Stage 1: E941 (Nitrogen) FIXATION OR VOLATILIZATION
In this stage, E941 (Nitrogen) moves from the atmosphere into the soil. 
Earth’s atmosphere contains a huge pool of E941 (Nitrogen) gas (N2). 

But this E941 (Nitrogen) is “unavailable” to plants, because the gaseous form cannot be used directly by plants without undergoing a transformation. 
To be used by plants, the N2 must be transformed through a process called E941 (Nitrogen) fixation. 
Fixation converts E941 (Nitrogen) in the atmosphere into forms that plants can absorb through their root systems.

A small amount of E941 (Nitrogen) can be fixed when lightning provides the energy needed for N2 to react with oxygen, producing E941 (Nitrogen) oxide, NO, and E941 (Nitrogen) dioxide, NO2. 
These forms of E941 (Nitrogen) then enter soils through rain or snow. 

E941 (Nitrogen) can also be fixed through the industrial process that creates fertilizer. 
This form of fixing occurs under high heat and pressure, during which atmospheric E941 (Nitrogen) and hydrogen are combined to form ammonia (NH3), which may then be processed further, to produce ammonium nitrate (NH4NO3), a form of E941 (Nitrogen) that can be added to soils and used by plants.

Most E941 (Nitrogen) fixation occurs naturally, in the soil, by bacteria. 
Some bacteria attach to plant roots and have a symbiotic (beneficial for both the plant and the bacteria) relationship with the plant. 

The bacteria get energy through photosynthesis and, in return, they fix E941 (Nitrogen) into a form the plant needs. 
The fixed E941 (Nitrogen) is then carried to other parts of the plant and is used to form plant tissues, so the plant can grow. 

Other bacteria live freely in soils or water and can fix E941 (Nitrogen) without this symbiotic relationship. 
These bacteria can also create forms of E941 (Nitrogen) that can be used by organisms.

Stage 2: MINERALIZATION
This stage takes place in the soil. 
E941 (Nitrogen) moves from organic materials, such as manure or plant materials to an inorganic form of E941 (Nitrogen) that plants can use. 
Eventually, the plant’s nutrients are used up and the plant dies and decomposes. 

This becomes important in the second stage of the E941 (Nitrogen) cycle. 
Mineralization happens when microbes act on organic material, such as animal manure or decomposing plant or animal material and begin to convert it to a form of E941 (Nitrogen) that can be used by plants. 

All plants under cultivation, except legumes.
A member of the pea family: beans, lentils, soybeans, peanuts and peas, are plants with seed pods that split in half. 
(plants with seed pods that split in half, such as lentils, beans, peas or peanuts) get the E941 (Nitrogen) they require through the soil. 
Legumes get E941 (Nitrogen) through fixation that occurs in their root nodules, as described above.

The first form of E941 (Nitrogen) produced by the process of mineralization is ammonia, NH3. 
The NH3 in the soil then reacts with water to form ammonium, NH4. 
This ammonium is held in the soils and is available for use by plants that do not get E941 (Nitrogen) through the symbiotic E941 (Nitrogen) fixing relationship described above.

Stage 3: NITRIFICATION
The third stage, nitrification, also occurs in soils. 
During nitrification the ammonia in the soils, produced during mineralization, is converted into compounds called nitrites, NO2−, and nitrates, NO3−. 

Nitrates can be used by plants and animals that consume the plants. 
Some bacteria in the soil can turn ammonia into nitrites. 
Although nitrite is not usable by plants and animals directly, other bacteria can change nitrites into nitrates—a form that is usable by plants and animals. 

This reaction provides energy for the bacteria engaged in this process. 
The bacteria that we are talking about are called nitrosomonas and nitrobacter. 
Nitrobacter turns nitrites into nitrates; nitrosomonas transform ammonia to nitrites. 

Both kinds of bacteria can act only in the presence of oxygen, O2. 
The process of nitrification is important to plants, as it produces an extra stash of available E941 (Nitrogen) that can be absorbed by the plants through their root systems.

Stage 4: IMMOBILIZATION
The fourth stage of the E941 (Nitrogen) cycle is immobilization, sometimes described as the reverse of mineralization. 
These two processes together control the amount of E941 (Nitrogen) in soils. 
Just like plants, microorganisms.

An organism, or living thing, that is too tiny to be seen without a microscope, such as a bacterium. 

Living in the soil require E941 (Nitrogen) as an energy source. 
These soil microorganisms pull E941 (Nitrogen) from the soil when the residues of decomposing plants do not contain enough E941 (Nitrogen). 

When microorganisms take in ammonium (NH4+) and nitrate (NO3−), these forms of E941 (Nitrogen) are no longer available to the plants and may cause E941 (Nitrogen) deficiency, or a lack of E941 (Nitrogen). 

Immobilization, therefore, ties up E941 (Nitrogen) in microorganisms. 
However, immobilization is important because it helps control and balance the amount of E941 (Nitrogen) in the soils by tying it up, or immobilizing the E941 (Nitrogen), in microorganisms.

Stage 5: DENITRIFICATION
In the fifth stage of the E941 (Nitrogen) cycle, E941 (Nitrogen) returns to the air as nitrates are converted to atmospheric E941 (Nitrogen) (N2) by bacteria through the process we call denitrification. 

This results in an overall loss of E941 (Nitrogen) from soils, as the gaseous form of E941 (Nitrogen) moves into the atmosphere, back where we began our story.


E941 (Nitrogen) IS CRUCIAL FOR LIFE!
The cycling of E941 (Nitrogen) through the ecosystem is crucial for maintaining productive and healthy ecosystems with neither too much nor too little E941 (Nitrogen). 
Plant production and biomass (living material) are limited by the availability of E941 (Nitrogen). 

Understanding how the plant-soil E941 (Nitrogen) cycle works can help us make better decisions about what crops to grow and where to grow them, so we have an adequate supply of food. 
Knowledge of the E941 (Nitrogen) cycle can also help us reduce pollution caused by adding too much fertilizer to soils. 

Certain plants can uptake more E941 (Nitrogen) or other nutrients, such as phosphorous, another fertilizer, and can even be used as a “buffer,” or filter, to prevent excessive fertilizer from entering waterways. 


As you have seen, not enough E941 (Nitrogen) in the soils leaves plants hungry, while too much of a good thing can be bad. 
Farmers and communities need to work to improve the uptake of added nutrients by crops and treat animal manure waste properly. 

We also need to protect the natural plant buffer zones that can take up E941 (Nitrogen) runoff before it reaches water bodies. 
But, our current patterns of clearing trees to build roads and other construction worsen this problem, because there are fewer plants left to uptake excess nutrients. 

We need to do further research to determine which plant species are best to grow in coastal areas to take up excess E941 (Nitrogen). We also need to find other ways to fix or avoid the problem of excess E941 (Nitrogen) spilling over into aquatic ecosystems. 

By working toward a more complete understanding of the E941 (Nitrogen) cycle and other cycles at play in Earth’s interconnected natural systems, we can better understand how to better protect Earth’s precious natural resources.

Some E941 (Nitrogen)-fixing organisms are free-living while others are symbiotic E941 (Nitrogen)-fixers, which require a close association with a host to carry out the process. 
Most of the symbiotic associations are very specific and have complex mechanisms that help to maintain the symbiosis. 

For example, root exudates from legume plants (e.g., peas, clover, soybeans) serve as a signal to certain species of Rhizobium, which are E941 (Nitrogen)-fixing bacteria. 

This signal attracts the bacteria to the roots, and a very complex series of events then occurs to initiate uptake of the bacteria into the root and trigger the process of E941 (Nitrogen) fixation in nodules that form on the roots.

Some of these bacteria are aerobic, others are anaerobic; some are phototrophic, others are chemotrophic (i.e., they use chemicals as their energy source instead of light). 

Although there is great physiological and phylogenetic diversity among the organisms that carry out E941 (Nitrogen) fixation, they all have a similar enzyme complex called E941 (Nitrogen)ase that catalyzes the reduction of N2 to NH3 (ammonia), which can be used as a genetic marker to identify the potential for E941 (Nitrogen) fixation. 

One of the characteristics of E941 (Nitrogen)ase is that the enzyme complex is very sensitive to oxygen and is deactivated in its presence. 
This presents an interesting dilemma for aerobic E941 (Nitrogen)-fixers and particularly for aerobic E941 (Nitrogen)-fixers that are also photosynthetic since they actually produce oxygen. 
Over time, E941 (Nitrogen)-fixers have evolved different ways to protect their E941 (Nitrogen)ase from oxygen. 

For example, some cyanobacteria have structures called heterocysts that provide a low-oxygen environment for the enzyme and serves as the site where all the E941 (Nitrogen) fixation occurs in these organisms. 
Other photosynthetic E941 (Nitrogen)-fixers fix E941 (Nitrogen) only at night when their photosystems are dormant and are not producing oxygen.

Genes for E941 (Nitrogen)ase are globally distributed and have been found in many aerobic habitats (e.g., oceans, lakes, soils) and also in habitats that may be anaerobic or microaerophilic (e.g., termite guts, sediments, hypersaline lakes, microbial mats, planktonic crustaceans). 

The broad distribution of E941 (Nitrogen)-fixing genes suggests that E941 (Nitrogen)-fixing organisms display a very broad range of environmental conditions, as might be expected for a process that is critical to the survival of all life on Earth.

NITRIFICATION:
Nitrification is the process that converts ammonia to nitrite and then to nitrate and is another important step in the global E941 (Nitrogen) cycle. 
Most nitrification occurs aerobically and is carried out exclusively by prokaryotes. 

There are two distinct steps of nitrification that are carried out by distinct types of microorganisms. 
The first step is the oxidation of ammonia to nitrite, which is carried out by microbes known as ammonia-oxidizers. 

Aerobic ammonia oxidizers convert ammonia to nitrite via the intermediate hydroxylamine, a process that requires two different enzymes, ammonia monooxygenase and hydroxylamine oxidoreductase. 

The process generates a very small amount of energy relative to many other types of metabolism; as a result, nitrosofiers are notoriously very slow growers. 
Additionally, aerobic ammonia oxidizers are also autotrophs, fixing carbon dioxide to produce organic carbon, much like photosynthetic organisms, but using ammonia as the energy source instead of light.


Unlike E941 (Nitrogen) fixation that is carried out by many different kinds of microbes, ammonia oxidation is less broadly distributed among prokaryotes. 
Until recently, it was thought that all ammonia oxidation was carried out by only a few types of bacteria in the genera Nitrosomonas, Nitrosospira, and Nitrosococcus. 

However, in 2005 an archaeon was discovered that could also oxidize ammonia. 
Since their discovery, ammonia-oxidizing Archaea have often been found to outnumber the ammonia-oxidizing Bacteria in many habitats. 

In the past several years, ammonia-oxidizing Archaea have been found to be abundant in oceans, soils, and salt marshes, suggesting an important role in the E941 (Nitrogen) cycle for these newly-discovered organisms. 

Currently, only one ammonia-oxidizing archaeon has been grown in pure culture, Nitrosopumilus maritimus, so our understanding of their physiological diversity is limited.

The second step in nitrification is the oxidation of nitrite (NO2-) to nitrate (NO3-). 
This step is carried out by a completely separate group of prokaryotes, known as nitrite-oxidizing Bacteria. 
Some of the genera involved in nitrite oxidation include Nitrospira, Nitrobacter, Nitrococcus, and Nitrospina. 

Similar to ammonia oxidizers, the energy generated from the oxidation of nitrite to nitrate is very small, and thus growth yields are very low. 

In fact, ammonia- and nitrite-oxidizers must oxidize many molecules of ammonia or nitrite in order to fix a single molecule of CO2. 
For complete nitrification, both ammonia oxidation and nitrite oxidation must occur.

Ammonia-oxidizers and nitrite-oxidizers are ubiquitous in aerobic environments. 
They have been extensively studied in natural environments such as soils, estuaries, lakes, and open-ocean environments. 

However, ammonia- and nitrite-oxidizers also play a very important role in wastewater treatment facilities by removing potentially harmful levels of ammonium that could lead to the pollution of the receiving waters. 

Much research has focused on how to maintain stable populations of these important microbes in wastewater treatment plants. Additionally, ammonia- and nitrite-oxidizers help to maintain healthy aquaria by facilitating the removal of potentially toxic ammonium excreted in fish urine.

ANAMMOX:
Traditionally, all nitrification was thought to be carried out under aerobic conditions, but recently a new type of ammonia oxidation occurring under anoxic conditions was discovered. 

Anammox (anaerobic ammonia oxidation) is carried out by prokaryotes belonging to the Planctomycetes phylum of Bacteria. 
The first described anammox bacterium was Brocadia anammoxidans. 
Anammox bacteria oxidize ammonia by using nitrite as the electron acceptor to produce gaseous E941 (Nitrogen). 

Anammox bacteria were first discovered in anoxic bioreactors of wasterwater treatment plants but have since been found in a variety of aquatic systems, including low-oxygen zones of the ocean, coastal and estuarine sediments, mangroves, and freshwater lakes. 

In some areas of the ocean, the anammox process is considered to be responsible for a significant loss of E941 (Nitrogen). 
Whether anammox or denitrification is responsible for most E941 (Nitrogen) loss in the ocean, it is clear that anammox represents an important process in the global E941 (Nitrogen) cycle.

DENITRIFICATION:
Denitrification is the process that converts nitrate to E941 (Nitrogen) gas, thus removing bioavailable E941 (Nitrogen) and returning it to the atmosphere. 
DiE941 (Nitrogen) gas (N2) is the ultimate end product of denitrification, but other intermediate gaseous forms of E941 (Nitrogen) exist. 

Unlike nitrification, denitrification is an anaerobic process, occurring mostly in soils and sediments and anoxic zones in lakes and oceans. 

Similar to E941 (Nitrogen) fixation, denitrification is carried out by a diverse group of prokaryotes, and there is recent evidence that some eukaryotes are also capable of denitrification. 

Some denitrifying bacteria include species in the genera Bacillus, Paracoccus, and Pseudomonas. 
Denitrifiers are chemoorganotrophs and thus must also be supplied with some form of organic carbon.

Denitrification is important in that it removes fixed E941 (Nitrogen) (i.e., nitrate) from the ecosystem and returns it to the atmosphere in a biologically inert form (N2). 
This is particularly important in agriculture where the loss of nitrates in fertilizer is detrimental and costly. 

However, denitrification in wastewater treatment plays a very beneficial role by removing unwanted nitrates from the wastewater effluent, thereby reducing the chances that the water discharged from the treatment plants will cause undesirable consequences (e.g., algal blooms).

AMMONIFICATION:
When an organism excretes waste or dies, the E941 (Nitrogen) in its tissues is in the form of organic E941 (Nitrogen) (e.g. amino acids, DNA).

Various fungi and prokaryotes then decompose the tissue and release inorganic E941 (Nitrogen) back into the ecosystem as ammonia in the process known as ammonification. 
The ammonia then becomes available for uptake by plants and other microorganisms for growth.

The E941 (Nitrogen) cycle, in which atmospheric E941 (Nitrogen) is converted into different E941 (Nitrogen)ous compounds, is one the most crucial natural processes to sustain living organisms. 
During the cycle, certain bacteria ‘fix’ atmospheric E941 (Nitrogen) into ammonia, which plants need in order to grow. 

Other bacteria convert the ammonia into amino acids and proteins. 
Animals eat the plants and consume the protein. 

E941 (Nitrogen) compounds return to the soil through animal and plant waste. 
Bacteria convert the waste E941 (Nitrogen) back to E941 (Nitrogen) gas, which returns to the atmosphere.

In an effort to make crops grow faster, people use E941 (Nitrogen) in fertilisers. 
The E941 (Nitrogen) cycle refers to the movement of E941 (Nitrogen) within and between the atmosphere, biosphere, hydrosphere and geosphere. 

The E941 (Nitrogen) cycle matters because E941 (Nitrogen) is an essential nutrient for sustaining life on Earth. 
E941 (Nitrogen) is a core component of amino acids, which are the building blocks of proteins, and of nucleic acids, which are the building blocks of genetic material (RNA and DNA). 

When other resources such as light and water are abundant, ecosystem productivity and biomass is often limited by the amount of available E941 (Nitrogen). 
This is the primary reason why E941 (Nitrogen) is an essential part of fertilizers used to enhance soil quality for agricultural activities.


E941 (Nitrogen) cycles through both the abiotic and biotic parts of the Earth system. 
The largest reservoir of E941 (Nitrogen) is found in the atmosphere, mostly as E941 (Nitrogen) gas (N2). 

E941 (Nitrogen) gas makes up 78% of the air we breathe. 
Most E941 (Nitrogen) enters ecosystems via certain kinds of bacteria in soil and plant roots that convert E941 (Nitrogen) gas into ammonia (NH3). 

This process is called E941 (Nitrogen) fixation. 
A very small amount of E941 (Nitrogen) is fixed via lightning interacting with the air. 
Once E941 (Nitrogen) is fixed, other types of bacteria convert ammonia to nitrate (NO3‑) and nitrite (NO2–), which can then be used by other bacteria and plants. 

Consumers (herbivores and predators) get E941 (Nitrogen) compounds from the plants and animals they eat. 
E941 (Nitrogen) returns to the soil when organisms release waste or die and are decomposed by bacteria and fungi. 

E941 (Nitrogen) is released back to the atmosphere by bacteria get their energy by breaking down nitrate and nitrite into E941 (Nitrogen) gas (also called denitrification).


FERTILIZER COMPONENT
E941 (Nitrogen) was discovered in 1772 by chemist and physician Daniel Rutherford, when he removed oxygen and carbon dioxide from air, demonstrating that the residual gas would not support living organisms or combustion, according to the Los Alamos National Laboratory. 

Other scientists, including Carl Wilhelm Scheele and Joseph Priestly, were working on the same problem, and called E941 (Nitrogen) "burnt" air, or air without oxygen. 
In 1786, Antoine Laurent de Lavoisier, called E941 (Nitrogen) "azote," which means "lifeless." 
This was based on the observation that E941 (Nitrogen) is the part of air cannot support life on E941 (Nitrogen)'s own. 

One of the most important E941 (Nitrogen) compounds is ammonia (NH3), which can be produced in the so-called Haber-Bosch process, in which E941 (Nitrogen) is reacted with hydrogen. 
The colorless ammonia gas with a pungent smell can be easily liquefied into a E941 (Nitrogen) fertilizer. 


THE E941 (Nitrogen) CYCLE
The E941 (Nitrogen) cycle, in which atmospheric E941 (Nitrogen) is converted into different organic compounds, is one the most crucial natural processes to sustain living organisms. 
During the cycle, bacteria in the soil process or "fix" atmospheric E941 (Nitrogen) into ammonia, which plants need in order to grow. 

Other bacteria convert the ammonia into amino acids and proteins. 
Then animals eat the plants and consume the protein. 

E941 (Nitrogen) compounds return to the soil through animal waste. 
Bacteria convert the waste E941 (Nitrogen) back to E941 (Nitrogen) gas, which returns to the atmosphere. 

A cycle is a sequence of events or steps that repeats itself regularly. 
In the E941 (Nitrogen) cycle, E941 (Nitrogen) moves from the soil to plants and then to animals and finally back to the soil. 
When E941 (Nitrogen) returns to the soil from a decaying plant E941 (Nitrogen) can be used again by another plant.


E941 (Nitrogen) Cycle has five general steps:
*E941 (Nitrogen) fixation
*Nitrification
*Denitrification
*E941 (Nitrogen) assimilation
*Ammonification.

Over many years the actions of people began changing how E941 (Nitrogen) cycled through nature. 
This changed the amount of E941 (Nitrogen) found in living organisms and in the air, soil, and water. 
The balance of nature was upset. 
By understanding how the E941 (Nitrogen) cycle works people can change their actions and protect the environment.

E941 (Nitrogen) can go through many transformations in the soil. 
These transformations are often grouped into a system called the E941 (Nitrogen) cycle, which can be presented in varying degrees of complexity. 

The E941 (Nitrogen) cycle is appropriate for understanding nutrient and fertilizer management. 
Because microorganisms are responsible for most of these processes, they occur very slowly, if at all, when soil temperatures are below 50° F, but their rates increase rapidly as soils become warmer.

The heart of the E941 (Nitrogen) cycle is the conversion of inorganic to organic E941 (Nitrogen), and vice versa. 
As microorganisms grow, they remove H₄⁺ and NO₃⁻ from the soil’s inorganic, available E941 (Nitrogen) pool, converting it to organic E941 (Nitrogen) in a process called immobilization. 

When these organisms die and are decomposed by others, excess NH₄⁺ can be released back to the inorganic pool in a process called mineralization. 
E941 (Nitrogen) can also be mineralized when microorganisms decompose a material containing more E941 (Nitrogen) than they can use at one time, materials such as legume residues or manures. 

Immobilization and mineralization are conducted by most microorganisms, and are most rapid when soils are warm and moist, but not saturated with water. 
The quantity of inorganic E941 (Nitrogen) available for crop use often depends on the amount of mineralization occurring and the balance between mineralization and immobilization.

Ammonium ions (NH₄⁺) not immobilized or taken up quickly by higher plants are usually converted rapidly to NO₃⁻ ions by a process called nitrification. 

This is a two-step process, during which bacteria called Nitrosomonas convert NH₄⁺ to nitrite (NO₂⁻), and then other bacteria, Nitrobacter, convert the NO₂⁻ to NO₃⁻. 

This process requires a well-aerated soil and occurs rapidly enough that one usually finds mostly NO₃⁻ rather than NH₄⁺ in soils during the growing season.

The E941 (Nitrogen) cycle contains several routes by which plant-available E941 (Nitrogen) can be lost from the soil. 
Nitrate-E941 (Nitrogen) is usually more subject to loss than is ammonium-E941 (Nitrogen). 
Significant loss mechanisms include leaching, denitrification, volatilization and crop removal.

The nitrate form of E941 (Nitrogen) is so soluble that it leaches easily when excess water percolates through the soil. 
This can be a major loss mechanism in coarse-textured soils where water percolates freely, but is less of a problem in finer-textured, more impermeable soils, where percolation is very slow.

These latter soils tend to become saturated easily, and when microorganisms exhaust the free oxygen supply in the wet soil, some obtain it by decomposing NO₃⁻. 

In this process, called denitrification, NO₃⁻ is converted to gaseous oxides of E941 (Nitrogen) or to N₂ gas, both unavailable to plants. 
Denitrification can cause major losses of E941 (Nitrogen) when soils are warm and remain saturated for more than a few days.

Losses of NH₄⁺ E941 (Nitrogen) are less common and occur mainly by volatilization. 
Ammonium ions are basically anhydrous ammonia (NH₃) molecules with an extra hydrogen ion (H⁺) attached. 

When this extra H⁺ is removed from the NH₄ ion by another ion such as hydroxyl (OH⁻), the resulting NH₃ molecule can evaporate, or volatilize from the soil. 
This mechanism is most important in high-pH soils that contain large quantities of OH⁻ ions.

Crop removal represents a loss because E941 (Nitrogen) in the harvested portions of the crop plant is removed from the field completely. 
The E941 (Nitrogen) in crop residues is recycled back into the system, and is better thought of as immobilized rather than removed. 
Much is eventually mineralized and may be reutilized by a crop.


PLANT E941 (Nitrogen) NEEDS AND UPTAKE
Plants absorb E941 (Nitrogen) from the soil as both NH₄⁺ and NO₃⁻ ions, but because nitrification is so pervasive in agricultural soils, most of the E941 (Nitrogen) is taken up as nitrate. 

Nitrate moves freely toward plant roots as they absorb water. 
Once inside the plant, NO₃⁻ is reduced to an NH₂ form and is assimilated to produce more complex compounds. 

Because plants require very large quantities of E941 (Nitrogen), an extensive root system is essential to allowing unrestricted uptake. 

Plants with roots restricted by compaction may show signs of E941 (Nitrogen) deficiency even when adequate E941 (Nitrogen) is present in the soil.

Most plants take E941 (Nitrogen) from the soil continuously throughout their lives, and E941 (Nitrogen) demand usually increases as plant size increases. 
A plant supplied with adequate E941 (Nitrogen) grows rapidly and produces large amounts of succulent, green foliage. 
Providing adequate E941 (Nitrogen) allows an annual crop, such as corn, to grow to full maturity, rather than delaying it. 

A E941 (Nitrogen)-deficient plant is generally small and develops slowly because it lacks the E941 (Nitrogen) necessary to manufacture adequate structural and genetic materials. 

It is usually pale green or yellowish because it lacks adequate chlorophyll. 
Older leaves often become necrotic and die as the plant moves E941 (Nitrogen) from less important older tissues to more important younger ones.

On the other hand, some plants may grow so rapidly when supplied with excessive E941 (Nitrogen) that they develop protoplasm faster than they can build sufficient supporting material in cell walls. 

Such plants are often rather weak and may be prone to mechanical injury. 
Development of weak straw and lodging of small grains are an example of such an effect.


FERTILIZER MANAGEMENT
E941 (Nitrogen) CYCLE:
E941 (Nitrogen) fertilizer rates are determined by the crop to be grown, yield goal and quantity of E941 (Nitrogen) that might be provided by the soil. 
Rates needed to achieve different yields with different crops vary by region, and such decisions are usually based on local recommendations and experience.


FACTORS THAT DETERMINE THE QUANTITY OF E941 (Nitrogen) SUPPLIED BY THE SOIL
The quantity of E941 (Nitrogen) released from the soil organic matter.

The quantity of E941 (Nitrogen) released by decomposition of residues of the previous crop.
Any E941 (Nitrogen) supplied by previous applications of organic waste.

Any E941 (Nitrogen) carried over from previous fertilizer applications.
Such contributions can be determined by taking E941 (Nitrogen) credits (expressed in lb/acre) for these variables. 

For example, corn following alfalfa usually requires less additional E941 (Nitrogen) than corn following corn, and less E941 (Nitrogen) fertilizer is needed to reach a given yield goal when manure is applied. 
As with rates, credits are usually based on local conditions.

Soil testing is being suggested more often as an alternative to taking E941 (Nitrogen) credits. 
Testing soils for E941 (Nitrogen) has been a useful practice in the drier regions of the Great Plains for many years, and in that region, fertilizer rates are often adjusted to account for NO₃⁻ found in the soil prior to planting. 

In recent years, there has been some interest in testing cornfields for NO₃⁻ in the more humid regions of the eastern United States and Canada, utilizing samples taken in late spring, after crop emergence, rather than before planting. 

This strategy, the pre-side-dress E941 (Nitrogen) soil test (PSNT), has received a great deal of publicity and seems to provide some indication of whether additional side-dressed E941 (Nitrogen) is needed or not.


FERTILIZER PLACEMENT
Placement decisions should maximize availability of E941 (Nitrogen) to crops and minimize potential losses. 
A plant’s roots usually will not grow across the root zone of another plant, so E941 (Nitrogen) must be placed where all plants have direct access to it. 

Broadcast applications accomplish this objective. 
Banding does also when all crop rows are directly next to a band. 

For corn, banding anhydrous ammonia or urea ammonium nitrate (UAN) in alternate row middles is usually as effective as banding in each middle because all rows have access to the fertilizer. 

Moist soil conditions are necessary for nutrient uptake. 
Placement below the soil surface can increase E941 (Nitrogen) availability under dry conditions because roots are more likely to find E941 (Nitrogen) in moist soil with such placement. 

Injecting side-dressed UAN may produce higher corn yields than surface application in years when dry weather follows side-dressing. 
In years when rainfall occurs shortly after application, subsurface placement is not as critical. 

Subsurface placement is normally used to control E941 (Nitrogen) losses. 
Anhydrous ammonia must be placed and sealed below the surface to eliminate direct volatilization losses of the gaseous ammonia. 

Volatilization from urea and UAN solutions can be controlled by incorporation or injection. 
Incorporating urea materials (mechanically or by rainfall shortly after application) is especially important in no-till situations in which volatilization is aggravated by large amounts of organic material on the soil surface. 

Placing E941 (Nitrogen) with phosphorus often increases phosphorus uptake, particularly when E941 (Nitrogen) is in the NH₄⁺ form and the crop is growing in an alkaline soil. 

The reasons for the effect are not completely clear, but may be due to E941 (Nitrogen) increasing root activity and potential for phosphorus uptake, and nitrification of NH₄⁺ providing acidity, which enhances phosphorus solubility. 


TIMING OF NUTRIENT APPLICATION
Timing has a major effect on the efficiency of E941 (Nitrogen) management systems. 
E941 (Nitrogen) should be applied to avoid periods of significant loss and to provide adequate E941 (Nitrogen) when the crop needs E941 (Nitrogen) most. 

Wheat takes up most of its E941 (Nitrogen) in the spring and early summer, and corn absorbs most E941 (Nitrogen) in midsummer, so ample availability at these times is critical. 

If losses are expected to be minimal, or can be effectively controlled, applications before or immediately after planting are effective for both crops. 

If significant losses, particularly those due to denitrification or leaching, are anticipated, split applications, in which much of the E941 (Nitrogen) is applied after crop emergence, can be effective in reducing losses. 

Fall applications for corn can be used on well-drained soils, particularly if the E941 (Nitrogen) is applied as anhydrous ammonia amended; however, fall applications should be avoided on poorly drained soils, due to an almost unavoidable potential for significant denitrification losses. 

When most of a crop’s E941 (Nitrogen) supply will be applied after significant crop growth or positioned away from the seed row (anhydrous ammonia or UAN banded in row middles), applying some E941 (Nitrogen) easily accessible to the seedling at planting ensures that the crop will not become E941 (Nitrogen) deficient before gaining access to the main supply of E941 (Nitrogen). 


MINIMIZING FERTILIZER LOSSES
The major mechanisms for E941 (Nitrogen) fertilizer loss are denitrification, leaching and volatilization. 
Denitrification and leaching occur under very wet soil conditions, while volatilization is most common when soils are only moist and are drying.


PRACTICES FOR AVOIDING E941 (Nitrogen) FERTILIZER LOSSES
Using an NH₄⁺ source of E941 (Nitrogen) acidifies the soil because the hydrogen ions (H⁺) released during nitrification of the NH₄⁺ are the major cause of acidity in soils. 
Over time, acidification and lowering of soil pH can become significant.

E941 (Nitrogen) fertilizers containing NO₃⁻ but no NH₄⁺ make the soil slightly less acidic over time, but are generally used in much lesser quantities than the others. 
The acidification due to NH₄⁻ E941 (Nitrogen) is a significant factor in the acidification of agricultural fields, but can easily be controlled by normal liming practices.


FERTILIZING LEGUMES WITH E941 (Nitrogen)
Because the Rhizobia bacteria that infect legume roots normally supply adequate E941 (Nitrogen) to the host plant, well-nodulated legumes rarely respond to additions of E941 (Nitrogen) fertilizer. 

Occasionally, however, soybeans may respond to applications of E941 (Nitrogen) late in the season, presumably because E941 (Nitrogen) fixation in the nodules has declined significantly. 
Such responses are quite erratic, though, and late-season applications of E941 (Nitrogen) to soybeans are not routinely recommended. 

The amount of atmospheric E941 (Nitrogen) fixed by non-symbiotic soil organisms varies with soil types, organic matter present and soil pH. 


E941 (Nitrogen) IN PLANTS
Healthy plants often contain 3 to 4 percent E941 (Nitrogen) in their above-ground tissues. 
This is a much higher concentration compared to other nutrients. 

Carbon, hydrogen and oxygen, nutrients that don’t play a significant role in most soil fertility management programs, are the only other nutrients present in higher concentrations.

E941 (Nitrogen) is so vital because E941 (Nitrogen) is a major component of chlorophyll, the compound by which plants use sunlight energy to produce sugars from water and carbon dioxide (i.e., photosynthesis). 
E941 (Nitrogen) is also a major component of amino acids, the building blocks of proteins. 

Without proteins, plants wither and die. 
Some proteins act as structural units in plant cells while others act as enzymes, making possible many of the biochemical reactions on which life is based. 

E941 (Nitrogen) is a component of energy-transfer compounds, such as ATP (adenosine triphosphate). 
ATP allows cells to conserve and use the energy released in metabolism. 

Finally, E941 (Nitrogen) is a significant component of nucleic acids such as DNA, the genetic material that allows cells (and eventually whole plants) to grow and reproduce. 
Without E941 (Nitrogen), there would be no life as we know it. 


SOIL E941 (Nitrogen)
Soil E941 (Nitrogen) exists in three general forms: organic E941 (Nitrogen) compounds, ammonium (NH₄⁺) ions and nitrate (NO₃⁻) ions.

At any given time, 95 to 99 percent of the potentially available E941 (Nitrogen) in the soil is in organic forms, either in plant and animal residues, in the relatively stable soil organic matter, or in living soil organisms, mainly microbes such as bacteria.

This E941 (Nitrogen) is not directly available to plants, but some can be converted to available forms by microorganisms. 
A very small amount of organic E941 (Nitrogen) may exist in soluble organic compounds, such as urea, that may be slightly available to plants.

The majority of plant-available E941 (Nitrogen) is in the inorganic forms NH₄⁺ and NO₃⁻ (sometimes called mineral E941 (Nitrogen)). Ammonium ions bind to the soil's negatively charged cation exchange complex (CEC) and behave much like other cations in the soil. 

Nitrate ions do not bind to the soil solids because they carry negative charges, but exist dissolved in the soil water, or precipitated as soluble salts under dry conditions.


NATURAL SOURCES OF SOIL E941 (Nitrogen)
The E941 (Nitrogen) in soil that might eventually be used by plants has two sources: E941 (Nitrogen)- containing minerals and the vast storehouse of E941 (Nitrogen) in the atmosphere. 
The E941 (Nitrogen) in soil minerals is released as the mineral decomposes. 

This process is generally quite slow, and contributes only slightly to E941 (Nitrogen) nutrition on most soils. 
On soils containing large quantities of NH₄⁺-rich clays (either naturally occurring or developed by fixation of NH₄⁺ added as fertilizer), however, E941 (Nitrogen) supplied by the mineral fraction may be significant in some years.

Atmospheric E941 (Nitrogen) is a major source of E941 (Nitrogen) in soils. 
In the atmosphere, E941 (Nitrogen) exists in the very inert N₂ form and must be converted before E941 (Nitrogen) becomes useful in the soil. 

The quantity of E941 (Nitrogen) added to the soil in this manner is directly related to thunderstorm activity, but most areas probably receive no more than 20 lb E941 (Nitrogen)/acre per year from this source.

Bacteria such as Rhizobia that infect (nodulate) the roots of, and receive much food energy from, legume plants can fix much more E941 (Nitrogen) per year (some well over 100 lb E941 (Nitrogen)/acre). 

When the quantity of E941 (Nitrogen) fixed by Rhizobia exceeds that needed by the microbes themselves, E941 (Nitrogen) is released for use by the host legume plant. 

This is why well-nodulated legumes do not often respond to additions of E941 (Nitrogen) fertilizer. 
They are already receiving enough from the bacteria.


PRODUCTION of E941 (Nitrogen):
E941 (Nitrogen) gas is an industrial gas produced by the fractional distillation of liquid air, or by mechanical means using gaseous air (pressurised reverse osmosis membrane or pressure swing adsorption). 

E941 (Nitrogen) gas generators using membranes or pressure swing adsorption (PSA) are typically more cost and energy efficient than bulk delivered E941 (Nitrogen). 
Commercial E941 (Nitrogen) is often a byproduct of air-processing for industrial concentration of oxygen for steelmaking and other purposes. 

When supplied compressed in cylinders it is often called OFN (oxygen-free E941 (Nitrogen)). 
Commercial-grade E941 (Nitrogen) already contains at most 20 ppm oxygen, and specially purified grades containing at most 2 ppm oxygen and 10 ppm argon are also available.

In a chemical laboratory, E941 (Nitrogen) is prepared by treating an aqueous solution of ammonium chloride with sodium nitrite.

NH4Cl + NaNO2 → N2 + NaCl + 2 H2O

Small amounts of the impurities NO and HNO3 are also formed in this reaction. 
The impurities can be removed by passing the gas through aqueous sulfuric acid containing potassium dichromate. 
Very pure E941 (Nitrogen) can be prepared by the thermal decomposition of barium azide or sodium azide.

2 NaN3 → 2 Na + 3 N2

Commercial production of E941 (Nitrogen) is largely by fractional distillation of liquefied air. 
The boiling temperature of E941 (Nitrogen) is −195.8 °C (−320.4 °F), about 13 °C (−23 °F) below that of oxygen, which is therefore left behind. 

E941 (Nitrogen) can also be produced on a large scale by burning carbon or hydrocarbons in air and separating the resulting carbon dioxide and water from the residual E941 (Nitrogen). 

On a small scale, pure E941 (Nitrogen) is made by heating barium azide, Ba(N3)2. 
Various laboratory reactions that yield E941 (Nitrogen) include heating ammonium nitrite (NH4NO2) solutions, oxidation of ammonia by bromine water, and oxidation of ammonia by hot cupric oxide.


OCCURRENCE of E941 (Nitrogen):
E941 (Nitrogen) is the most common pure element in the earth, making up 78.1% of the volume of the atmosphere (75.5% by mass), around 3.89 million gigatonnes. 

Despite this, E941 (Nitrogen) is not very abundant in Earth's crust, making up somewhere around 19 parts per million of this, on par with niobium, gallium, and lithium. 
(This represents 300,000 to a million gigatonnes of E941 (Nitrogen), depending on the mass of the crust.) 

The only important E941 (Nitrogen) minerals are nitre (potassium nitrate, saltpetre) and soda nitre (sodium nitrate, Chilean saltpetre). 
However, these have not been an important source of nitrates since the 1920s, when the industrial synthesis of ammonia and nitric acid became common.

E941 (Nitrogen) compounds constantly interchange between the atmosphere and living organisms. 
E941 (Nitrogen) must first be processed, or "fixed", into a plant-usable form, usually ammonia. 

Some E941 (Nitrogen) fixation is done by lightning strikes producing the E941 (Nitrogen) oxides, but most is done by diazotrophic bacteria through enzymes known as E941 (Nitrogen)ases (although today industrial E941 (Nitrogen) fixation to ammonia is also significant). 

When the ammonia is taken up by plants, E941 (Nitrogen) is used to synthesise proteins. 
These plants are then digested by animals who use the E941 (Nitrogen) compounds to synthesise their proteins and excrete E941 (Nitrogen)-bearing waste. 

Finally, these organisms die and decompose, undergoing bacterial and environmental oxidation and denitrification, returning free diE941 (Nitrogen) to the atmosphere. 

Industrial E941 (Nitrogen) fixation by the Haber process is mostly used as fertiliser, although excess E941 (Nitrogen)–bearing waste, when leached, leads to eutrophication of freshwater and the creation of marine dead zones, as E941 (Nitrogen)-driven bacterial growth depletes water oxygen to the point that all higher organisms die. 
Furthermore, nitrous oxide, which is produced during denitrification, attacks the atmospheric ozone layer.

Many saltwater fish manufacture large amounts of trimethylamine oxide to protect them from the high osmotic effects of their environment; conversion of this compound to dimethylamine is responsible for the early odour in unfresh saltwater fish. 

In animals, free radical nitric oxide (derived from an amino acid), serves as an important regulatory molecule for circulation.

Nitric oxide's rapid reaction with water in animals results in the production of its metabolite nitrite. 
Animal metabolism of E941 (Nitrogen) in proteins, in general, results in the excretion of urea, while animal metabolism of nucleic acids results in the excretion of urea and uric acid. 

The characteristic odour of animal flesh decay is caused by the creation of long-chain, E941 (Nitrogen)-containing amines, such as putrescine and cadaverine, which are breakdown products of the amino acids ornithine and lysine, respectively, in decaying proteins.


OCCURRENCE AND DISTRIBUTION of E941 (Nitrogen):
Among the elements, E941 (Nitrogen) ranks sixth in cosmic abundance. 
The atmosphere of Earth consists of 75.51 percent by weight (or 78.09 percent by volume) of E941 (Nitrogen); this is the principal source of E941 (Nitrogen) for commerce and industry. 

The atmosphere also contains varying small amounts of ammonia and ammonium salts, as well as E941 (Nitrogen) oxides and nitric acid (the latter substances being formed in electrical storms and in the internal combustion engine). 

Free E941 (Nitrogen) is found in many meteorites; in gases of volcanoes, mines, and some mineral springs; in the Sun; and in some stars and nebulae.

E941 (Nitrogen) also occurs in mineral deposits of nitre or saltpetre (potassium nitrate, KNO3) and Chile saltpetre (sodium nitrate, NaNO3), but these deposits exist in quantities that are wholly inadequate for human needs. 
Another material rich in E941 (Nitrogen) is guano, found in bat caves and in dry places frequented by birds. 

In combination, E941 (Nitrogen) is found in the rain and soil as ammonia and ammonium salts and in seawater as ammonium (NH4+), nitrite (NO2−), and nitrate (NO3−) ions.

E941 (Nitrogen) constitutes on the average about 16 percent by weight of the complex organic compounds known as proteins, present in all living organisms. 

The natural abundance of E941 (Nitrogen) in Earth’s crust is 0.3 part per 1,000. 
The cosmic abundance—the estimated total abundance in the universe—is between three and seven atoms per atom of silicon, which is taken as the standard.

India, Russia, the United States, Trinidad and Tobago, and Ukraine were the top five producers of E941 (Nitrogen) (in the form of ammonia) in the early 21st century.


ALLOTROPES of E941 (Nitrogen):
Atomic E941 (Nitrogen), also known as active E941 (Nitrogen), is highly reactive, being a triradical with three unpaired electrons. 

Free E941 (Nitrogen) atoms easily react with most elements to form nitrides, and even when two free E941 (Nitrogen) atoms collide to produce an excited N2 molecule, they may release so much energy on collision with even such stable molecules as carbon dioxide and water to cause homolytic fission into radicals such as CO and O or OH and H. 

Atomic E941 (Nitrogen) is prepared by passing an electric discharge through E941 (Nitrogen) gas at 0.1–2 mmHg, which produces atomic E941 (Nitrogen) along with a peach-yellow emission that fades slowly as an afterglow for several minutes even after the discharge terminates.

Given the great reactivity of atomic E941 (Nitrogen), elemental E941 (Nitrogen) usually occurs as molecular N2, diE941 (Nitrogen). 
E941 (Nitrogen) is a colourless, odourless, and tasteless diamagnetic gas at standard conditions: E941 (Nitrogen) melts at −210 °C and boils at −196 °C. 

DiE941 (Nitrogen) is mostly unreactive at room temperature, but E941 (Nitrogen) will nevertheless react with lithium metal and some transition metal complexes. 
This is due to its bonding, which is unique among the diatomic elements at standard conditions in that it has an N≡N triple bond. 

Triple bonds have short bond lengths (in this case, 109.76 pm) and high dissociation energies (in this case, 945.41 kJ/mol), and are thus very strong, explaining diE941 (Nitrogen)'s low level of chemical reactivity.

Other E941 (Nitrogen) oligomers and polymers may be possible. 
If they could be synthesised, they may have potential applications as materials with a very high energy density, that could be used as powerful propellants or explosives. 

Under extremely high pressures (1.1 million atm) and high temperatures (2000 K), as produced in a diamond anvil cell, E941 (Nitrogen) polymerises into the single-bonded cubic gauche crystal structure. 

This structure is similar to that of diamond, and both have extremely strong covalent bonds, resulting in its nickname "E941 (Nitrogen) diamond".

At atmospheric pressure, molecular E941 (Nitrogen) condenses (liquefies) at 77 K (−195.79 °C) and freezes at 63 K (−210.01 °C) into the beta hexagonal close-packed crystal allotropic form. 
Below 35.4 K (−237.6 °C) E941 (Nitrogen) assumes the cubic crystal allotropic form (called the alpha phase). 

Liquid E941 (Nitrogen), a colourless fluid resembling water in appearance, but with 80.8% of the density (the density of liquid E941 (Nitrogen) at its boiling point is 0.808 g/mL), is a common cryogen. 

Solid E941 (Nitrogen) has many crystalline modifications. 
E941 (Nitrogen) forms a significant dynamic surface coverage on Pluto and outer moons of the Solar System such as Triton. 

Even at the low temperatures of solid E941 (Nitrogen) it is fairly volatile and can sublime to form an atmosphere, or condense back into E941 (Nitrogen) frost. 
E941 (Nitrogen) is very weak and flows in the form of glaciers and on Triton geysers of E941 (Nitrogen) gas come from the polar ice cap region.

DIE941 (Nitrogen) COMPLEXES:
The first example of a diE941 (Nitrogen) complex to be discovered was [Ru(NH3)5(N2)]2+ (see figure at right), and soon many other such complexes were discovered. 

These complexes, in which a E941 (Nitrogen) molecule donates at least one lone pair of electrons to a central metal cation, illustrate how N2 might bind to the metal(s) in E941 (Nitrogen)ase and the catalyst for the Haber process: these processes involving diE941 (Nitrogen) activation are vitally important in biology and in the production of fertilisers.

DiE941 (Nitrogen) is able to coordinate to metals in five different ways. 
The more well-characterised ways are the end-on M←N≡N (η1) and M←N≡N→M (μ, bis-η1), in which the lone pairs on the E941 (Nitrogen) atoms are donated to the metal cation. 

The less well-characterised ways involve diE941 (Nitrogen) donating electron pairs from the triple bond, either as a bridging ligand to two metal cations (μ, bis-η2) or to just one (η2). 

The fifth and unique method involves triple-coordination as a bridging ligand, donating all three electron pairs from the triple bond (μ3-N2). 
A few complexes feature multiple N2 ligands and some feature N2 bonded in multiple ways. 

Since N2 is isoelectronic with carbon monoxide (CO) and acetylene (C2H2), the bonding in diE941 (Nitrogen) complexes is closely allied to that in carbonyl compounds, although N2 is a weaker σ-donor and π-acceptor than CO. 

Theoretical studies show that σ donation is a more important factor allowing the formation of the M–N bond than π back-donation, which mostly only weakens the N–N bond, and end-on (η1) donation is more readily accomplished than side-on (η2) donation.

Today, diE941 (Nitrogen) complexes are known for almost all the transition metals, accounting for several hundred compounds. 
They are normally prepared by three methods:

Replacing labile ligands such as H2O, H−, or CO directly by E941 (Nitrogen): these are often reversible reactions that proceed at mild conditions.

Reducing metal complexes in the presence of a suitable coligand in excess under E941 (Nitrogen) gas. 
A common choice include replacing chloride ligands by dimethylphenylphosphine (PMe2Ph) to make up for the smaller number of E941 (Nitrogen) ligands attached than the original chlorine ligands.

Converting a ligand with N–N bonds, such as hydrazine or azide, directly into a diE941 (Nitrogen) ligand.
Occasionally the N≡N bond may be formed directly within a metal complex, for example by directly reacting coordinated ammonia (NH3) with nitrous acid (HNO2), but this is not generally applicable. 

Most diE941 (Nitrogen) complexes have colours within the range white-yellow-orange-red-brown; a few exceptions are known, such as the blue [{Ti(η5-C5H5)2}2-(N2)].


E941 (Nitrogen) AND WATER:
Nutrients, such as E941 (Nitrogen) and phosphorus, are essential for plant and animal growth and nourishment, but the overabundance of certain nutrients in water can cause a number of adverse health and ecological effects. 

E941 (Nitrogen), in the forms of nitrate, nitrite, or ammonium, is a nutrient needed for plant growth. 
About 78% of the air that we breathe is composed of E941 (Nitrogen) gas, and in some areas of the United States, particularly the northeast, certain forms of E941 (Nitrogen) are commonly deposited in acid rain.

Of course, E941 (Nitrogen) is used in agriculture to grow crops, and on many farms the landscape has been greatly modified to maximize farming output. 
Fields have been leveled and modified to efficiently drain off excess water that may fall as precipitation or from irrigation practices.

E941 (Nitrogen) is transported in water and can also be stored in sediments and plants, including algae. 
Algal blooms (both macroalgae and microalgae) and increased plant growth occur in areas with increased nutrients and high light availability.

Different parts of the landscape process dissolved and particulate E941 (Nitrogen) differently depending on the soils, vegetation, hydrology, and sources of E941 (Nitrogen) and carbon. 
Some land units and land uses contribute E941 (Nitrogen) to waterways, others, like wetlands, remove it.

E941 (Nitrogen), total(organic and inorganic) is not a single chemical substance but a wide range of compounds of E941 (Nitrogen) which can be used directly by plants as a source of E941 (Nitrogen) required for their nutrition directly, or else may be converted into forms that plants can use in the environment.

E941 (Nitrogen) gas makes up about 80% of the atmosphere and is fairly non-reactive. 
Before living organisms can make use of E941 (Nitrogen) as a nutrient element, E941 (Nitrogen) has to be in a soluble form, such as nitrate or ammonia (inorganic forms) or in organic forms such as proteins which are readily converted into inorganic forms. 

The key inorganic form of E941 (Nitrogen) is ammonia, a highly reactive gas in its pure form, but which is usually found as ammonium ions when dissolved in water. 

Ammonium ions are the form of E941 (Nitrogen) used by plants and animals to make amino acids which are then built up into the structural proteins and enzymes that are the key components of all living organisms. 

The other main inorganic form of E941 (Nitrogen) is the nitrate ion (derived from nitric acid). 
Nitrate and ammonia are inter-converted in the water and soil by micro-organisms. 
These inorganic forms are taken up by plants and converted to proteins. 

Higher animals could not use inorganic forms of E941 (Nitrogen) for their nutrition but instead depend on organic forms already made by the plants and other animals that they eat. 

Proteins in the animal diet are first broken down into their constituent amino acids and are then reassembled into the required animal proteins and other cell constituents. 

Waste organic E941 (Nitrogen) compounds in animals are converted into ammonia, and then excreted in the urine as urea and other simple organic forms. 
These substances then enter the environment where they are converted into nitrate, ammonium ions and E941 (Nitrogen) gas. 

Some specialised bacteria can also 'fix' E941 (Nitrogen) gas from the atmosphere into ammonium ions. 
The above process is called the E941 (Nitrogen) cycle. 
In addition to ammonium and nitrate ions, traces of unstable inorganic E941 (Nitrogen) compounds such as nitrite ions may occasionally be found.


SOURCES of E941 (Nitrogen):
Although E941 (Nitrogen) is abundant naturally in the environment, E941 (Nitrogen) is also introduced through sewage and fertilizers. 

Chemical fertilizers or animal manure is commonly applied to crops to add nutrients. 
It may be difficult or expensive to retain on site all E941 (Nitrogen) brought on to farms for feed or fertilizer and generated by animal manure. 

Unless specialized structures have been built on the farms, heavy rains can generate runoff containing these materials into nearby streams and lakes. 
Wastewater-treatment facilities that do not specifically remove E941 (Nitrogen) can also lead to excess levels of E941 (Nitrogen) in surface or groundwater.

Nitrate can get into water directly as the result of runoff of fertilizers containing nitrate. 
Some nitrate enters water from the atmosphere, which carries E941 (Nitrogen)-containing compounds derived from automobiles and other sources. 

More than 3 million tons of E941 (Nitrogen) are deposited in the United States each year from the atmosphere, derived either naturally from chemical reactions or from the combustion of fossil fuels, such as coal and gasoline. 

Nitrate can also be formed in water bodies through the oxidation of other forms of E941 (Nitrogen), including nitrite, ammonia, and organic E941 (Nitrogen) compounds such as amino acids. 
Ammonia and organic E941 (Nitrogen) can enter water through sewage effluent and runoff from land where manure has been applied or stored.

E941 (Nitrogen) appears as a colorless odorless gas. Noncombustible and nontoxic. 
Makes up the major portion of the atmosphere, but will not support life by itself. 
Used in food processing, in purging air conditioning and refrigeration systems, and in pressurizing aircraft tires. 


NITRIDES, AZIDES, and NITRIDO COMPLEXES of E941 (Nitrogen):
E941 (Nitrogen) bonds to almost all the elements in the periodic table except the first three noble gases, helium, neon, and argon, and some of the very short-lived elements after bismuth, creating an immense variety of binary compounds with varying properties and applications. 

Many binary compounds are known: with the exception of the E941 (Nitrogen) hydrides, oxides, and fluorides, these are typically called nitrides. 
Many stoichiometric phases are usually present for most elements (e.g. MnN, Mn6N5, Mn3N2, Mn2N, Mn4N, and MnxN for 
9.2 < x < 25.3). 

They may be classified as "salt-like" (mostly ionic), covalent, "diamond-like", and metallic (or interstitial), although this classification has limitations generally stemming from the continuity of bonding types instead of the discrete and separate types that it implies. 

They are normally prepared by directly reacting a metal with E941 (Nitrogen) or ammonia (sometimes after heating), or by thermal decomposition of metal amides:

3 Ca + N2 → Ca3N2
3 Mg + 2 NH3 → Mg3N2 + 3 H2 (at 900 °C)
3 Zn(NH2)2 → Zn3N2 + 4 NH3

Many variants on these processes are possible. 
The most ionic of these nitrides are those of the alkali metals and alkaline earth metals, Li3N (Na, K, Rb, and Cs do not form stable nitrides for steric reasons) and M3N2 (M = Be, Mg, Ca, Sr, Ba). 

These can formally be thought of as salts of the N3− anion, although charge separation is not actually complete even for these highly electropositive elements.
However, the alkali metal azides NaN3 and KN3, featuring the linear N−3 anion, are well-known, as are Sr(N3)2 and Ba(N3)2. 

Azides of the B-subgroup metals (those in groups 11 through 16) are much less ionic, have more complicated structures, and detonate readily when shocked.

Many covalent binary nitrides are known. 
Examples include cyanogen ((CN)2), triphosphorus pentanitride (P3N5), disulfur dinitride (S2N2), and tetrasulfur tetranitride (S4N4). 

The essentially covalent silicon nitride (Si3N4) and germanium nitride (Ge3N4) are also known: silicon nitride in particular would make a promising ceramic if not for the difficulty of working with and sintering it. 

In particular, the group 13 nitrides, most of which are promising semiconductors, are isoelectronic with graphite, diamond, and silicon carbide and have similar structures: their bonding changes from covalent to partially ionic to metallic as the group is descended. 

In particular, since the B–N unit is isoelectronic to C–C, and carbon is essentially intermediate in size between boron and E941 (Nitrogen), much of organic chemistry finds an echo in boron–E941 (Nitrogen) chemistry, such as in borazine ("inorganic benzene"). 

Nevertheless, the analogy is not exact due to the ease of nucleophilic attack at boron due to its deficiency in electrons, which is not possible in a wholly carbon-containing ring.

The largest category of nitrides are the interstitial nitrides of formulae MN, M2N, and M4N (although variable composition is perfectly possible), where the small E941 (Nitrogen) atoms are positioned in the gaps in a metallic cubic or hexagonal close-packed lattice. 

They are opaque, very hard, and chemically inert, melting only at very high temperatures (generally over 2500 °C). 
They have a metallic lustre and conduct electricity as do metals. 
They hydrolyse only very slowly to give ammonia or E941 (Nitrogen).

The nitride anion (N3−) is the strongest π donor known amongst ligands (the second-strongest is O2−). 
Nitrido complexes are generally made by thermal decomposition of azides or by deprotonating ammonia, and they usually involve a terminal {≡N}3− group. 

The linear azide anion (N−3), being isoelectronic with nitrous oxide, carbon dioxide, and cyanate, forms many coordination complexes. Further catenation is rare, although N4−4 (isoelectronic with carbonate and nitrate) is known.


HYDRIDES of E941 (Nitrogen):
Industrially, ammonia (NH3) is the most important compound of E941 (Nitrogen) and is prepared in larger amounts than any other compound, because it contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilisers. 

It is a colourless alkaline gas with a characteristic pungent smell. 
The presence of hydrogen bonding has very significant effects on ammonia, conferring on it its high melting (−78 °C) and boiling (−33 °C) points. 

As a liquid, it is a very good solvent with a high heat of vaporisation (enabling it to be used in vacuum flasks), that also has a low viscosity and electrical conductivity and high dielectric constant, and is less dense than water. 

However, the hydrogen bonding in NH3 is weaker than that in H2O due to the lower electronegativity of E941 (Nitrogen) compared to oxygen and the presence of only one lone pair in NH3 rather than two in H2O. 
It is a weak base in aqueous solution (pKb 4.74); its conjugate acid is ammonium, NH+4. 
It can also act as an extremely weak acid, losing a proton to produce the amide anion, NH−2. 

It thus undergoes self-dissociation, similar to water, to produce ammonium and amide. 
Ammonia burns in air or oxygen, though not readily, to produce E941 (Nitrogen) gas; it burns in fluorine with a greenish-yellow flame to give E941 (Nitrogen) trifluoride. 

Reactions with the other nonmetals are very complex and tend to lead to a mixture of products. 
Ammonia reacts on heating with metals to give nitrides.

Many other binary E941 (Nitrogen) hydrides are known, but the most important are hydrazine (N2H4) and hydrogen azide (HN3). 
Although it is not a E941 (Nitrogen) hydride, hydroxylamine (NH2OH) is similar in properties and structure to ammonia and hydrazine as well. 

Hydrazine is a fuming, colourless liquid that smells similarly to ammonia. 
Its physical properties are very similar to those of water (melting point 2.0 °C, boiling point 113.5 °C, density 1.00 g/cm3). 

Despite it being an endothermic compound, it is kinetically stable. 
It burns quickly and completely in air very exothermically to give E941 (Nitrogen) and water vapour. 
It is a very useful and versatile reducing agent and is a weaker base than ammonia. 

It is also commonly used as a rocket fuel.
Hydrazine is generally made by reaction of ammonia with alkaline sodium hypochlorite in the presence of gelatin or glue:

NH3 + OCl− → NH2Cl + OH−
NH2Cl + NH3 → N2H+5 + Cl− (slow)
N2H+5 + OH− → N2H4 + H2O (fast)

(The attacks by hydroxide and ammonia may be reversed, thus passing through the intermediate NHCl− instead.) 
The reason for adding gelatin is that it removes metal ions such as Cu2+ that catalyses the destruction of hydrazine by reaction with monochloramine (NH2Cl) to produce ammonium chloride and E941 (Nitrogen).

Hydrogen azide (HN3) was first produced in 1890 by the oxidation of aqueous hydrazine by nitrous acid. 
It may be considered the conjugate acid of the azide anion, and is similarly analogous to the hydrohalic acids.


HALIDES and OXOHALIDES of E941 (Nitrogen):
All four simple E941 (Nitrogen) trihalides are known. 
A few mixed halides and hydrohalides are known, but are mostly unstable; examples include NClF2, NCl2F, NBrF2, NF2H, NFH2, NCl2H, and NClH2.

Five E941 (Nitrogen) fluorides are known. 
E941 (Nitrogen) trifluoride (NF3, first prepared in 1928) is a colourless and odourless gas that is thermodynamically stable, and most readily produced by the electrolysis of molten ammonium fluoride dissolved in anhydrous hydrogen fluoride. 

Like carbon tetrafluoride, it is not at all reactive and is stable in water or dilute aqueous acids or alkalis. 
Only when heated does it act as a fluorinating agent, and it reacts with copper, arsenic, antimony, and bismuth on contact at high temperatures to give tetrafluorohydrazine (N2F4). 

The cations NF+4 and N2F+3 are also known (the latter from reacting tetrafluorohydrazine with strong fluoride-acceptors such as arsenic pentafluoride), as is ONF3, which has aroused interest due to the short N–O distance implying partial double bonding and the highly polar and long N–F bond. 

Tetrafluorohydrazine, unlike hydrazine itself, can dissociate at room temperature and above to give the radical NF2•. 
Fluorine azide (FN3) is very explosive and thermally unstable. 

DiE941 (Nitrogen) difluoride (N2F2) exists as thermally interconvertible cis and trans isomers, and was first found as a product of the thermal decomposition of FN3.

E941 (Nitrogen) trichloride (NCl3) is a dense, volatile, and explosive liquid whose physical properties are similar to those of carbon tetrachloride, although one difference is that NCl3 is easily hydrolysed by water while CCl4 is not. 

It was first synthesised in 1811 by Pierre Louis Dulong, who lost three fingers and an eye to its explosive tendencies. 
As a dilute gas it is less dangerous and is thus used industrially to bleach and sterilise flour. 
E941 (Nitrogen) tribromide (NBr3), first prepared in 1975, is a deep red, temperature-sensitive, volatile solid that is explosive even at −100 °C. 

E941 (Nitrogen) triiodide (NI3) is still more unstable and was only prepared in 1990. 
Its adduct with ammonia, which was known earlier, is very shock-sensitive: it can be set off by the touch of a feather, shifting air currents, or even alpha particles. 

For this reason, small amounts of E941 (Nitrogen) triiodide are sometimes synthesised as a demonstration to high school chemistry students or as an act of "chemical magic". 
Chlorine azide (ClN3) and bromine azide (BrN3) are extremely sensitive and explosive.

Two series of E941 (Nitrogen) oxohalides are known: the nitrosyl halides (XNO) and the nitryl halides (XNO2). 
The first are very reactive gases that can be made by directly halogenating nitrous oxide. 
Nitrosyl fluoride (NOF) is colourless and a vigorous fluorinating agent. 

Nitrosyl chloride (NOCl) behaves in much the same way and has often been used as an ionising solvent. 
Nitrosyl bromide (NOBr) is red. The reactions of the nitryl halides are mostly similar: nitryl fluoride (FNO2) and nitryl chloride (ClNO2) are likewise reactive gases and vigorous halogenating agents.


OXIDES of E941 (Nitrogen):
E941 (Nitrogen) forms nine molecular oxides, some of which were the first gases to be identified: N2O (nitrous oxide), NO (nitric oxide), N2O3 (diE941 (Nitrogen) trioxide), NO2 (E941 (Nitrogen) dioxide), N2O4 (diE941 (Nitrogen) tetroxide), N2O5 (diE941 (Nitrogen) pentoxide), N4O (nitrosylazide), and N(NO2)3 (trinitramide). 

All are thermally unstable towards decomposition to their elements. 
One other possible oxide that has not yet been synthesised is oxatetrazole (N4O), an aromatic ring.

Nitrous oxide (N2O), better known as laughing gas, is made by thermal decomposition of molten ammonium nitrate at 250 °C. This is a redox reaction and thus nitric oxide and E941 (Nitrogen) are also produced as byproducts. 

It is mostly used as a propellant and aerating agent for sprayed canned whipped cream, and was formerly commonly used as an anaesthetic. 
Despite appearances, it cannot be considered to be the anhydride of hyponitrous acid (H2N2O2) because that acid is not produced by the dissolution of nitrous oxide in water. 

It is rather unreactive (not reacting with the halogens, the alkali metals, or ozone at room temperature, although reactivity increases upon heating) and has the unsymmetrical structure N–N–O (N≡N+O−↔−N=N+=O): above 600 °C it dissociates by breaking the weaker N–O bond. 

Nitric oxide (NO) is the simplest stable molecule with an odd number of electrons. 
In mammals, including humans, it is an important cellular signaling molecule involved in many physiological and pathological processes. 

It is formed by catalytic oxidation of ammonia. 
It is a colourless paramagnetic gas that, being thermodynamically unstable, decomposes to E941 (Nitrogen) and oxygen gas at 1100–1200 °C. 

Its bonding is similar to that in E941 (Nitrogen), but one extra electron is added to a π* antibonding orbital and thus the bond order has been reduced to approximately 2.5; hence dimerisation to O=N–N=O is unfavourable except below the boiling point (where the cis isomer is more stable) because it does not actually increase the total bond order and because the unpaired electron is delocalised across the NO molecule, granting it stability. 

There is also evidence for the asymmetric red dimer O=N–O=N when nitric oxide is condensed with polar molecules. 
It reacts with oxygen to give brown E941 (Nitrogen) dioxide and with halogens to give nitrosyl halides. 
It also reacts with transition metal compounds to give nitrosyl complexes, most of which are deeply coloured.

Blue diE941 (Nitrogen) trioxide (N2O3) is only available as a solid because it rapidly dissociates above its melting point to give nitric oxide, E941 (Nitrogen) dioxide (NO2), and diE941 (Nitrogen) tetroxide (N2O4). 

The latter two compounds are somewhat difficult to study individually because of the equilibrium between them, although sometimes diE941 (Nitrogen) tetroxide can react by heterolytic fission to nitrosonium and nitrate in a medium with high dielectric constant. 

E941 (Nitrogen) dioxide is an acrid, corrosive brown gas. 
Both compounds may be easily prepared by decomposing a dry metal nitrate. 
Both react with water to form nitric acid. 

DiE941 (Nitrogen) tetroxide is very useful for the preparation of anhydrous metal nitrates and nitrato complexes, and it became the storable oxidiser of choice for many rockets in both the United States and USSR by the late 1950s. 

This is because it is a hypergolic propellant in combination with a hydrazine-based rocket fuel and can be easily stored since it is liquid at room temperature.

The thermally unstable and very reactive diE941 (Nitrogen) pentoxide (N2O5) is the anhydride of nitric acid, and can be made from it by dehydration with phosphorus pentoxide. 
It is of interest for the preparation of explosives. 

It is a deliquescent, colourless crystalline solid that is sensitive to light. 
In the solid state it is ionic with structure [NO2]+[NO3]−; as a gas and in solution it is molecular O2N–O–NO2. 

Hydration to nitric acid comes readily, as does analogous reaction with hydrogen peroxide giving peroxonitric acid (HOONO2). 
It is a violent oxidising agent. 
Gaseous diE941 (Nitrogen) pentoxide decomposes as follows:

N2O5 ⇌ NO2 + NO3 → NO2 + O2 + NO
N2O5 + NO ⇌ 3 NO2


OXOACIDS, OXOANIONS, and OXOACID SALTS of E941 (Nitrogen):
Many E941 (Nitrogen) oxoacids are known, though most of them are unstable as pure compounds and are known only as aqueous solution or as salts. 

Hyponitrous acid (H2N2O2) is a weak diprotic acid with the structure HON=NOH (pKa1 6.9, pKa2 11.6). 
Acidic solutions are quite stable but above pH 4 base-catalysed decomposition occurs via [HONNO]− to nitrous oxide and the hydroxide anion. 

Hyponitrites (involving the N2O2−2 anion) are stable to reducing agents and more commonly act as reducing agents themselves. 
They are an intermediate step in the oxidation of ammonia to nitrite, which occurs in the E941 (Nitrogen) cycle. 
Hyponitrite can act as a bridging or chelating bidentate ligand.


Nitrous acid (HNO2) is not known as a pure compound, but is a common component in gaseous equilibria and is an important aqueous reagent: its aqueous solutions may be made from acidifying cool aqueous nitrite (NO−2, bent) solutions, although already at room temperature disproportionation to nitrate and nitric oxide is significant. 
It is a weak acid with pKa 3.35 at 18 °C. 

They may be titrimetrically analysed by their oxidation to nitrate by permanganate. 
They are readily reduced to nitrous oxide and nitric oxide by sulfur dioxide, to hyponitrous acid with tin(II), and to ammonia with hydrogen sulfide. 
Salts of hydrazinium N2H+5 react with nitrous acid to produce azides which further react to give nitrous oxide and E941 (Nitrogen). 

Sodium nitrite is mildly toxic in concentrations above 100 mg/kg, but small amounts are often used to cure meat and as a preservative to avoid bacterial spoilage. 
It is also used to synthesise hydroxylamine and to diazotise primary aromatic amines as follows:

ArNH2 + HNO2 → [ArNN]Cl + 2 H2O
Nitrite is also a common ligand that can coordinate in five ways. 
The most common are nitro (bonded from the E941 (Nitrogen)) and nitrito (bonded from an oxygen). 
Nitro-nitrito isomerism is common, where the nitrito form is usually less stable.

Nitric acid (HNO3) is by far the most important and the most stable of the E941 (Nitrogen) oxoacids. 
It is one of the three most used acids (the other two being sulfuric acid and hydrochloric acid) and was first discovered by the alchemists in the 13th century. 

It is made by catalytic oxidation of ammonia to nitric oxide, which is oxidised to E941 (Nitrogen) dioxide, and then dissolved in water to give concentrated nitric acid. 

In the United States of America, over seven million tonnes of nitric acid are produced every year, most of which is used for nitrate production for fertilisers and explosives, among other uses. 

Anhydrous nitric acid may be made by distilling concentrated nitric acid with phosphorus pentoxide at low pressure in glass apparatus in the dark. 

It can only be made in the solid state, because upon melting it spontaneously decomposes to E941 (Nitrogen) dioxide, and liquid nitric acid undergoes self-ionisation to a larger extent than any other covalent liquid as follows:

2 HNO3 ⇌ H2NO+3 + NO−3 ⇌ H2O + [NO2]+ + [NO3]−

Two hydrates, HNO3·H2O and HNO3·3H2O, are known that can be crystallised. 
It is a strong acid and concentrated solutions are strong oxidising agents, though gold, platinum, rhodium, and iridium are immune to attack. 

A 3:1 mixture of concentrated hydrochloric acid and nitric acid, called aqua regia, is still stronger and successfully dissolves gold and platinum, because free chlorine and nitrosyl chloride are formed and chloride anions can form strong complexes. 

In concentrated sulfuric acid, nitric acid is protonated to form nitronium, which can act as an electrophile for aromatic nitration:

HNO3 + 2 H2SO4 ⇌ NO+2 + H3O+ + 2 HSO−4

The thermal stabilities of nitrates (involving the trigonal planar NO−3 anion) depends on the basicity of the metal, and so do the products of decomposition (thermolysis), which can vary between the nitrite (for example, sodium), the oxide (potassium and lead), or even the metal itself (silver) depending on their relative stabilities. 

Nitrate is also a common ligand with many modes of coordination.
Finally, although orthonitric acid (H3NO4), which would be analogous to orthophosphoric acid, does not exist, the tetrahedral orthonitrate anion NO3−4 is known in its sodium and potassium salts:

These white crystalline salts are very sensitive to water vapour and carbon dioxide in the air:

Na3NO4 + H2O + CO2 → NaNO3 + NaOH + NaHCO3
Despite its limited chemistry, the orthonitrate anion is interesting from a structural point of view due to its regular tetrahedral shape and the short N–O bond lengths, implying significant polar character to the bonding.


ORGANIC E941 (Nitrogen) COMPOUNDS:
E941 (Nitrogen) is one of the most important elements in organic chemistry. 

Many organic functional groups involve a carbon–E941 (Nitrogen) bond, such as amides (RCONR2), amines (R3N), imines (RC(=NR)R), imides (RCO)2NR, azides (RN3), azo compounds (RN2R), cyanates and isocyanates (ROCN or RCNO), nitrates (RONO2), nitriles and isonitriles (RCN or RNC), nitrites (RONO), nitro compounds (RNO2), nitroso compounds (RNO), oximes (RCR=NOH), and pyridine derivatives. 

C–N bonds are strongly polarised towards E941 (Nitrogen). 
In these compounds, E941 (Nitrogen) is usually trivalent (though it can be tetravalent in quaternary ammonium salts, R4N+), with a lone pair that can confer basicity on the compound by being coordinated to a proton. 

This may be offset by other factors: for example, amides are not basic because the lone pair is delocalised into a double bond (though they may act as acids at very low pH, being protonated at the oxygen), and pyrrole is not acidic because the lone pair is delocalised as part of an aromatic ring. 

The amount of E941 (Nitrogen) in a chemical substance can be determined by the Kjeldahl method. 
In particular, E941 (Nitrogen) is an essential component of nucleic acids, amino acids and thus proteins, and the energy-carrying molecule adenosine triphosphate and is thus vital to all life on Earth.


Although the other applications are important, by far the greatest bulk of elemental E941 (Nitrogen) is consumed in the manufacture of E941 (Nitrogen) compounds. 

The triple bond between atoms in the E941 (Nitrogen) molecules is so strong (226 kilocalories per mole, more than twice that of molecular hydrogen) that it is difficult to cause molecular E941 (Nitrogen) to enter into other combinations.

The chief commercial method of fixing E941 (Nitrogen) (incorporating elemental E941 (Nitrogen) into compounds) is the Haber-Bosch process for synthesizing ammonia. 

This process was developed during World War I to lessen the dependence of Germany on Chilean nitrate. 
E941 (Nitrogen) involves the direct synthesis of ammonia from its elements.


With oxygen, E941 (Nitrogen) forms several oxides, including nitrous oxide, N2O, in which E941 (Nitrogen) is in the +1 oxidation state; nitric oxide, NO, in which it is in the +2 state; and E941 (Nitrogen) dioxide, NO2, in which it is in the +4 state. 

Sodium nitrate (NaNO3) and potassium nitrate (KNO3) are formed by the decomposition of organic matter with compounds of these metals present. 

In certain dry areas of the world these saltpeters are found in quantity and are used as fertilizers. 
Other inorganic E941 (Nitrogen) compounds are nitric acid (HNO3), ammonia (NH3), the oxides (NO, NO2, N2O4, N2O), cyanides (CN-), etc.

The E941 (Nitrogen) cycle is one of the most important processes in nature for living organisms. 
Although E941 (Nitrogen) gas is relatively inert, bacteria in the soil are capable of “fixing” the E941 (Nitrogen) into a usable form (as a fertilizer) for plants. 
In other words, Nature has provided a method to produce E941 (Nitrogen) for plants to grow. 

Animals eat the plant material where the E941 (Nitrogen) has been incorporated into their system, primarily as protein. 
The cycle is completed when other bacteria convert the waste E941 (Nitrogen) compounds back to E941 (Nitrogen) gas. 
E941 (Nitrogen) is crucial to life, as it is a component of all proteins.


E941 (Nitrogen) FIXATION:
E941 (Nitrogen) gas (N2) makes up nearly 80% of the Earth's atmosphere, yet E941 (Nitrogen) is often the nutrient that limits primary production in many ecosystems. 
Why is this so? 
Because plants and animals are not able to use E941 (Nitrogen) gas in that form. 

For E941 (Nitrogen) to be available to make proteins, DNA, and other biologically important compounds, E941 (Nitrogen) must first be converted into a different chemical form. 
The process of converting N2 into biologically available E941 (Nitrogen) is called E941 (Nitrogen) fixation. 

N2 gas is a very stable compound due to the strength of the triple bond between the E941 (Nitrogen) atoms, and E941 (Nitrogen) requires a large amount of energy to break this bond. 
The whole process requires eight electrons and at least sixteen ATP molecules. 

As a result, only a select group of prokaryotes are able to carry out this energetically demanding process. 
Although most E941 (Nitrogen) fixation is carried out by prokaryotes, some E941 (Nitrogen) can be fixed abiotically by lightning or certain industrial processes, including the combustion of fossil fuels.


E941 (Nitrogen) AND THE CNO CYCLE:
When the universe’s first generation of stars was born, they contained only the elements made in the big bang: hydrogen, helium, and a tiny amount of lithium.

As these stars burned, they synthesized heavier elements, such as carbon. 
Supernovae then spread the heavier elements out into galaxies where more stars were born.

Carbon from supernovae plays a crucial role in the way many second and higher generation stars burn. 
In stars whose mass is higher than about 1.1 – 1.5 times that of our sun, carbon-12 catalyzes the fusion of hydrogen to helium – i.e. carbon-12 takes part in the fusion reaction, but is not consumed by it.

As you can see on the left, carbon-12 is regenerated at the end of each cycle, the net result of which is that four hydrogen nuclei are consumed and one helium nucleus is produced. 
This reaction is called the CNO cycle.

Over time, each carbon-12 nucleus can take part in a very large number of cycles. 
A proportion of E941 (Nitrogen) made during the CNO cycle evades further reaction. 

At the end of a star’s life, this E941 (Nitrogen) may be distributed into the galaxy. 
In our solar system the E941 (Nitrogen) from a star that died billions of years ago ended up as an essential element in proteins and DNA and formed about 80 percent of our planet’s atmosphere.


INTERESTING FACTS ABOUT E941 (Nitrogen):
-About 2.5 percent of the weight of living organisms comes from E941 (Nitrogen) in organic molecules.
-Many of the molecules of life contain E941 (Nitrogen). 
E941 (Nitrogen) is the fourth most abundant element in the human body.


-The E941 (Nitrogen) compound nitroglycerin can be used for relief of angina, a life threatening heart condition.
-Neptune’s satellite Triton has five mile high, E941 (Nitrogen)-powered geysers.
-E941 (Nitrogen) is the seventh most abundant element in the universe.


-Like Earth, Triton’s atmosphere is mainly E941 (Nitrogen), but Triton is so cold the E941 (Nitrogen) sits on the surface as a rock-hard solid. 
The solid E941 (Nitrogen) allows the feeble light arriving from the sun to pass through it. 

Dark impurities in the E941 (Nitrogen) ice or in darker rocks below the ice warm up slightly in the sunlight, melting and vaporizing the solid E941 (Nitrogen), which eventually breaks through the solid E941 (Nitrogen) as geysers which push ice particles one to five miles above Triton’s frozen surface.


-In 1919, the world learned for the first time that atomic nuclei could be disintegrated. 
Ernest Rutherford reported that he had bombarded E941 (Nitrogen) gas with alpha-particles (helium nuclei) and found hydrogen was produced. 
(Further research by Patrick Blackett showed that the alpha particles had transmuted E941 (Nitrogen)-14 to oxygen-17 plus hydrogen.)
-The universe’s E941 (Nitrogen) was made, and is being made, by the CNO cycle in stars heavier than our sun. 


HISTORY of E941 (Nitrogen):
E941 (Nitrogen) compounds have a very long history, ammonium chloride having been known to Herodotus. 
They were well known by the Middle Ages. 

Alchemists knew nitric acid as aqua fortis (strong water), as well as other E941 (Nitrogen) compounds such as ammonium salts and nitrate salts. 

The mixture of nitric and hydrochloric acids was known as aqua regia (royal water), celebrated for its ability to dissolve gold, the king of metals.

The discovery of E941 (Nitrogen) is attributed to the Scottish physician Daniel Rutherford in 1772, who called it noxious air. Though he did not recognise it as an entirely different chemical substance, he clearly distinguished it from Joseph Black's "fixed air", or carbon dioxide. 

The fact that there was a component of air that does not support combustion was clear to Rutherford, although he was not aware that it was an element. 

E941 (Nitrogen) was also studied at about the same time by Carl Wilhelm Scheele, Henry Cavendish, and Joseph Priestley, who referred to E941 (Nitrogen) as burnt air or phlogisticated air. 

French chemist Antoine Lavoisier referred to E941 (Nitrogen) gas as "mephitic air" or azote, from the Greek word άζωτικός (azotikos), "no life", due to E941 (Nitrogen) being asphyxiant. 
In an atmosphere of pure E941 (Nitrogen), animals died and flames were extinguished. 

Though Lavoisier's name was not accepted in English since it was pointed out that all gases but oxygen are either asphyxiant or outright toxic, it is used in many languages (French, Italian, Portuguese, Polish, Russian, Albanian, Turkish, etc.; the German Stickstoff similarly refers to the same characteristic, viz. ersticken "to choke or suffocate") and still remains in English in the common names of many E941 (Nitrogen) compounds, such as hydrazine and compounds of the azide ion. 


Finally, it led to the name "pnictogens" for the group headed by E941 (Nitrogen), from the Greek πνίγειν "to choke".
The English word E941 (Nitrogen) (1794) entered the language from the French nitrogène, coined in 1790 by French chemist Jean-Antoine Chaptal (1756–1832), from the French nitre (potassium nitrate, also called saltpeter) and the French suffix -gène, "producing", from the Greek -γενής (-genes, "begotten"). 

Chaptal's meaning was that E941 (Nitrogen) is the essential part of nitric acid, which in turn was produced from nitre. 
In earlier times, niter had been confused with Egyptian "natron" (sodium carbonate) – called νίτρον (nitron) in Greek – which, despite the name, contained no nitrate.

The earliest military, industrial, and agricultural applications of E941 (Nitrogen) compounds used saltpeter (sodium nitrate or potassium nitrate), most notably in gunpowder, and later as fertiliser. 

In 1910, Lord Rayleigh discovered that an electrical discharge in E941 (Nitrogen) gas produced "active E941 (Nitrogen)", a monatomic allotrope of E941 (Nitrogen). 
The "whirling cloud of brilliant yellow light" produced by his apparatus reacted with mercury to produce explosive mercury nitride.

For a long time, sources of E941 (Nitrogen) compounds were limited. 
Natural sources originated either from biology or deposits of nitrates produced by atmospheric reactions. 

E941 (Nitrogen) fixation by industrial processes like the Frank–Caro process (1895–1899) and Haber–Bosch process (1908–1913) eased this shortage of E941 (Nitrogen) compounds, to the extent that half of global food production (see Applications) now relies on synthetic E941 (Nitrogen) fertilisers. 

At the same time, use of the Ostwald process (1902) to produce nitrates from industrial E941 (Nitrogen) fixation allowed the large-scale industrial production of nitrates as feedstock in the manufacture of explosives in the World Wars of the 20th century.


About four-fifths of Earth’s atmosphere is E941 (Nitrogen), which was isolated and recognized as a specific substance during early investigations of the air. 

Carl Wilhelm Scheele, a Swedish chemist, showed in 1772 that air is a mixture of two gases, one of which he called “fire air,” because it supported combustion, and the other “foul air,” because it was left after the “fire air” had been used up. 
The “fire air” was, of course, oxygen and the “foul air” E941 (Nitrogen). 

At about the same time, E941 (Nitrogen) also was recognized by a Scottish botanist, Daniel Rutherford (who was the first to publish his findings), by the British chemist Henry Cavendish, and by the British clergyman and scientist Joseph Priestley, who, with Scheele, is given credit for the discovery of oxygen. 

Later work showed the new gas to be a constituent of nitre, a common name for potassium nitrate (KNO3), and, accordingly, it was named E941 (Nitrogen) by the French chemist Jean-Antoine-Claude Chaptal in 1790. 

E941 (Nitrogen) first was considered a chemical element by Antoine-Laurent Lavoisier, whose explanation of the role of oxygen in combustion eventually overthrew the phlogiston theory, an erroneous view of combustion that became popular in the early 18th century. 

The inability of E941 (Nitrogen) to support life (Greek: zoe) led Lavoisier to name it azote, still the French equivalent of E941 (Nitrogen).


E941 (Nitrogen) was discovered by the Scottish physician Daniel Rutherford in 1772. 
E941 (Nitrogen) is the fifth most abundant element in the universe and makes up about 78% of the earth's atmosphere, which contains an estimated 4,000 trillion tons of the gas. 

E941 (Nitrogen) is obtained from liquefied air through a process known as fractional distillation.
The largest use of E941 (Nitrogen) is for the production of ammonia (NH3). 
Large amounts of E941 (Nitrogen) are combined with hydrogen to produce ammonia in a method known as the Haber process. 

The French chemist Antoine Laurent Lavoisier named E941 (Nitrogen) azote, meaning "without life". 
The name became E941 (Nitrogen), which derives from the Greek word nitron, which means "native soda" and genes, which means "forming". 

Credit for the discovery of the element is generally given to Daniel Rutherford, who found it could be separated from air in 1772.
E941 (Nitrogen) was sometimes referred to as "burnt" or "dephlogisticated" air, since air that no longer contains oxygen is almost all E941 (Nitrogen). 

The other gases in air are present in much lower concentrations.
E941 (Nitrogen) compounds are found in foods, fertilizers, poisons, and explosives. 
Your body is 3% E941 (Nitrogen) by weight. 

All living organisms contain E941 (Nitrogen).
E941 (Nitrogen) is responsible for the orange-red, blue-green, blue-violet, and deep violet colors of the aurora.
One way to prepare E941 (Nitrogen) gas is by liquefaction and fractional distillation from the atmosphere. 

Liquid E941 (Nitrogen) boils at 77 K (−196 °C, −321 °F). 
E941 (Nitrogen) freezes at 63 K (-210.01 °C).
Liquid E941 (Nitrogen) is a cryogenic fluid, capable of freezing skin on contact. 

While the Leidenfrost effect protects skin from very brief exposure (less than one second), ingesting liquid E941 (Nitrogen) can cause severe injury. 
When liquid E941 (Nitrogen) is used to make ice cream, the E941 (Nitrogen) vaporizes. 
E941 (Nitrogen) has a valence of 3 or 5. 

E941 (Nitrogen) forms negatively charged ions (anions) that readily react with other nonmetals to form covalent bonds.
Saturn's largest moon, Titan, is the only moon in the solar system with a dense atmosphere. 
E941 (Nitrogen)'s atmosphere consists of over 98% E941 (Nitrogen).

From the Latin word nitrum, Greek Nitron, native soda; and genes, forming. 
E941 (Nitrogen) was discovered by chemist and physician Daniel Rutherford in 1772. 
He removed oxygen and carbon dioxide from air and showed that the residual gas would not support combustion or living organisms. 

At the same time there were other noted scientists working on the problem of E941 (Nitrogen). 
These included Scheele, Cavendish, Priestley, and others. 
They called it "burnt" or" dephlogisticated air," which meant air without oxygen.


DISCOVERY of E941 (Nitrogen):
Dr. Doug Stewart
In 1674 the English physician John Mayow demonstrated that air is not a single element, it is made up of different substances. 
He did this by showing that only a part of air is combustible. 
Most of E941 (Nitrogen) is not. 

Almost a century later, Scottish chemist Joseph Black carried out more detailed work on air. 
After removing oxygen and carbon dioxide, part of the air remained.

Black used burning phosphorus as the final step in oxygen removal. 
(Burning phosphorus has a very high affinity for oxygen and is efficient at removing it completely.) 
Black then assigned further study of the gases in air to his doctoral student, Daniel Rutherford. 

Rutherford built on Black’s work and in a series of steps thoroughly removed oxygen and carbon dioxide from air. 
He showed that, like carbon dioxide, the residual gas could not support combustion or living organisms. 

Unlike carbon dioxide, however, E941 (Nitrogen) was insoluble in water and alkali solutions. 
Rutherford reported his discovery in 1772 of ‘noxious air,’ which we now call E941 (Nitrogen). 

Swedish pharmacist Carl Scheele discovered E941 (Nitrogen) independently, calling it spent air.
Scheele absorbed oxygen in a number of ways, including using a mixture of sulfur and iron filings and burning phosphorus. 

After removing the oxygen, he reported a residual gas which would not support combustion and had between two-thirds and three-quarters of the volume of the original air. 
Scheele published his results in 1777, although it is thought the work was carried out in 1772. 

Although Rutherford and Scheele are now jointly credited with E941 (Nitrogen)’s discovery, E941 (Nitrogen) appears to have been discovered earlier by Henry Cavendish, but not published.

Prior to 1772 (the precise date is unknown – Priestley refers to it in his work “Experiments and Observations Made in and Before the Year 1772”) Cavendish wrote to Joseph Priestley describing ‘burnt air’.

The ‘burnt air’ had been prepared by passing air repeatedly over red hot charcoal (removing the oxygen) and then bubbling the remaining gas through a solution of caustic potash (potassium hydroxide) which would have removed the carbon dioxide.

Cavendish wrote: “The specific gravity of this air was found to differ very little from that of common air; of the two, it seemed rather lighter. 

E941 (Nitrogen) extinguished flame, and rendered common air unfit for making bodies burn in the same manner as fixed air, but in a less degree, as a candle which burnt about 80″ in pure common air, and which went out immediately in common air mixed with 6/55 of fixed air, burnt about 26″ in common air mixed with the same portion of this burnt air.” 

In 1790 the French chemist Jean-Antoine-Claude Chaptal named the element ‘E941 (Nitrogen)’ after experiments showed it to be a constituent of nitre, as potassium nitrate was called then.


PHYSICAL and CHEMICAL PROPERTIES of E941 (Nitrogen):
Appearance: colorless gas, liquid or solid
Standard atomic weight Ar°(N): [14.00643, 14.00728] 14.007±0.001 (abridged)
Atomic number (Z): 7
Group    group: 15 (pnictogens)
Period    period: 2
Block: p-block
Electron configuration: [He] 2s2 2p3
Electrons per shell: 2, 5
Phase at STP: gas


Melting point: (N2) 63.23[2] K ​(−209.86[2] °C, ​−345.75[2] °F)
Boiling point: (N2) 77.355 K ​(−195.795 °C, ​−320.431 °F)
Density (at STP): 1.2506 g/L[3] at 0 °C, 1013 mbar
when liquid (at b.p.): 0.808 g/cm3
Triple point: 63.151 K, ​12.52 kPa
Critical point: 126.21 K, 3.39 MPa
Heat of fusion: (N2) 0.72 kJ/mol
Heat of vaporisation: (N2) 5.57 kJ/mol
Molar heat capacity: (N2) 29.124 J/(mol·K)


Oxidation states: −3, −2, −1, 0,[4] +1, +2, +3, +4, +5 (a strongly acidic oxide)
Electronegativity: Pauling scale: 3.04
Ionisation energies:
1st: 1402.3 kJ/mol
2nd: 2856 kJ/mol
3rd: 4578.1 kJ/mol
Covalent radius: 71±1 pm
Van der Waals radius: 155 pm
Natural occurrence: primordial


Crystal structure: ​hexagonalHexagonal crystal structure for E941 (Nitrogen)
Speed of sound: 353 m/s (gas, at 27 °C)
Thermal conductivity: 25.83×10−3 W/(m⋅K)
Magnetic ordering: diamagnetic
Molecular Weight: 28.014    
XLogP3-AA: 0.1    
Hydrogen Bond Donor Count: 0    
Hydrogen Bond Acceptor Count: 2    
Rotatable Bond Count: 0    


Exact Mass: 28.006148008    
Monoisotopic Mass: 28.006148008    
Topological Polar Surface Area: 47.6 Ų    
Heavy Atom Count: 2    
Formal Charge: 0    
Complexity: 8    
Isotope Atom Count: 0    
Defined Atom Stereocenter Count: 0    
Undefined Atom Stereocenter Count: 0    


Defined Bond Stereocenter Count: 0    
Undefined Bond Stereocenter Count: 0    
Covalently-Bonded Unit Count: 1    
Compound Is Canonicalized: Yes
Atomic number: 7
Atomic mass: 14.0067 g.mol -1
Electronegativity according to Pauling: 3.0
Density: 1.25*10-3 g.cm-3 at 20°C
Melting point: -210 °C


Boiling point: -195.8 °C
Vanderwaals radius: 0.092 nm
Ionic radius: 0.171 nm (-3) ; 0.011 (+5) ; 0.016 (+3)
Isotopes: 4
Electronic shell: [ He ] 2s22p3
Energy of first ionisation: 1402 kJ.mol -1
Energy of second ionisation: 2856 kJ.mol -1
Energy of third ionisation: 4578 kJ.mol -1
Discovered by: Rutherford in 1772


Chemical formula : N 2
Purity level : ≥ 99.9%
Relative density (air = 1) : 0.97
Aspect : colorless gas
Odor : odorless gas
Limit of flammability in air : not flammable
Appearance Form: Compressed gas
Color: colorless
Odo:r odorless
Odor Threshold: No data available

pH: No data available
Melting point/freezing point: -209,99 °C
Initial boiling point and boiling range: -195,79 °C
Flash point: Not applicable
Evaporation rate: No data available
Flammability (solid, gas): No data available
Upper/lower flammability or explosive limits: No data available
Vapor pressure: No data available
Vapor density: No data available


Relative density: 0,97 g/cm3
Water solubility: No data available
Partition coefficient: n-octanol/water: No data available
Autoignition temperature: No data available
Decomposition temperature: No data available
Viscosity: No data available
Explosive properties: No data available
Oxidizing properties: No data available
Other safety information: No data available


Atomic number (number of protons in the nucleus): 7
Atomic symbol (on the Periodic Table of Elements): N
Atomic weight (average mass of the atom): 14.0067
Density: 0.0012506 grams per cubic centimeter
Phase at room temperature: Gas
Melting point: minus 321 degrees Fahrenheit (minus 210 degrees Celsius)
Boiling point: minus 320.42 F (minus 195.79 C)
Number of isotopes (atoms of the same element with a different number of neutrons): 16 including 2 stable ones
Most common isotopes: E941 (Nitrogen)-14 (Abundance: 99.63 percent)


FIRST AID MEASURES of E941 (Nitrogen):
-Description of first-aid measures:
*General advice:
Consult a physician. 

*If inhaled:
If breathed in, move person into fresh air. 
Consult a physician.

*In case of skin contact:
Wash off with soap and plenty of water. 
Consult a physician.

*In case of eye contact:
Flush eyes with water as a precaution.

*If swallowed:
Rinse mouth with water. 
Consult a physician.

-Indication of any immediate medical attention and special treatment needed:
No data available


ACCIDENTAL RELEASE MEASURES of E941 (Nitrogen):
-Environmental precautions:
Do not let product enter drains.

-Methods and materials for containment and cleaning up:
Clean up promptly by sweeping or vacuum.


FIRE FIGHTING MEASURES of E941 (Nitrogen):
-Extinguishing media:
*Suitable extinguishing media:
Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.

-Further information:
Use water spray to cool unopened containers.


EXPOSURE CONTROLS/PERSONAL PROTECTION of E941 (Nitrogen):
-Control parameters:
--Ingredients with workplace control parameters:
-Exposure controls:
--Appropriate engineering controls:
Handle in accordance with good industrial hygiene and safety practice. 
Wash hands before breaks and at the end of workday.

--Personal protective equipment:
*Eye/face protection:
Use equipment for eye protection.

*Skin protection:
Handle with gloves. 
Wash and dry hands.

-Control of environmental exposure:
Do not let product enter drains.


HANDLING and STORAGE of E941 (Nitrogen):
-Conditions for safe storage, including any incompatibilities:
Store in cool place. 
Keep container tightly closed in a dry and well-ventilated place.
Contents under pressure.


STABILITY and REACTIVITY of E941 (Nitrogen):
-Reactivity:
No data available

-Chemical stability:
Stable under recommended storage conditions.

-Possibility of hazardous reactions:
No data available

-Conditions to avoid:
No data available


SYNONYMS:
N
E941 (Nitrogen)
E941 (Nitrogen) gas
Molecular E941 (Nitrogen)
DiE941 (Nitrogen)
E941 (Nitrogen)-14
E941 (Nitrogen) molecule
Diatomic E941 (Nitrogen)
E941 (Nitrogen), liquid
UNII-N762921K75
N2
CHEBI:17997
N762921K75
MOL E941 (Nitrogen)
E941 (Nitrogen)o
E941 (Nitrogen) [NF]
E941 (Nitrogen) (liquified)
HSDB 5060
UN1066
UN1977
E941 (Nitrogen) (TN)
E941 (Nitrogen), elemental
E941 (Nitrogen) (n2)
E941 (Nitrogen), compressed
E941 (Nitrogen) (JP17/NF)
E941 (Nitrogen), >=99.998%
E941 (Nitrogen), >=99.999%
CHEMBL142438
INS NO.941
DTXSID4036304
INS-941
DB09152
UN 1066
UN 1977
E941
E941 (Nitrogen), Messer(R) CANGas, 99.999%
E-941
C00697
D00083
E941 (Nitrogen), refrigerated liquid (cryogenic liquid)
E941 (Nitrogen), compressed [UN1066] [Nonflammable gas]
Q2370426
UNII-K21NZZ5Y0B component IJGRMHOSHXDMSA-UHFFFAOYSA-N
E941 (Nitrogen), refrigerated liquid (cryogenic liquid) [UN1977] [Nonflammable gas]
N#N

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