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Silver oxide is the chemical compound with the formula Ag2O. Silver oxide is a fine black or dark brown powder that is used to prepare other silver compounds.Silver oxide is a highly insoluble thermally stable Silver source suitable for glass, optic and ceramic applications. Silver oxide is a photosensetive fine black powder that decomposes High Purity (99.999%) Silver Oxide (Ag2O)Powderabove 280 °. Oxide compounds are not conductive to electricity. However, certain perovskite structured oxides are electronically conductive finding application in the cathode of solid oxide fuel cells and oxygen generation systems.
CAS Number:20667-12-3
SYNONYMS
Silver(I) oxide; Argentous oxide; Silver oxide (Ag2O); MFCD00003404; Disilver oxide; Silver(1+) oxide; Silberoxyd; silver;hydrate; EINECS 243-957-1; Silver oxide (ous); Silver(I) oxide 99+%; DTXSID40893897; Silver(I) oxide, Electrical Grade; Silver(I) oxide, ReagentPlus(R), 99%; EC 243-957-1; Silver(I) oxide, SAJ first grade, >=98.0%; Silver(I) oxide, >=99.99% trace metals basis; Silver(I) oxide, SAJ special grade, >=99.0%; Silver(I) oxide, purum p.a., >=99.0% (AT)
Silver oxide can be prepared by combining aqueous solutions of silver nitrate and an alkali hydroxide. This reaction does not afford appreciable amounts of silver hydroxide due to the favorable energetics for the following reaction. With suitably controlled conditions, this reaction can be used to prepare Ag2O powder with properties suitable for several uses including as a fine grained conductive paste filler. Ag2O features linear, two-coordinate Ag centers linked by tetrahedral oxides. Silver oxide is isostructural with Cu2O. Silver oxide "dissolves" in solvents that degrade Silver Oxide. Silver oxide is slightly soluble in water due to the formation of the ion Ag(OH)−. 2 and possibly related hydrolysis products. Silver oxide is soluble in ammonia solution, producing active compound of Tollens' reagent. A slurry of Ag2O is readily attacked by acids
Where HX = HF, HCl, HBr, HI, or CF3COOH. Silver oxide will also react with solutions of alkali chlorides to precipitate silver chloride, leaving a solution of the corresponding alkali hydroxide. Like many silver compounds, silver oxide is photosensitive. Silver oxide also decomposes at temperatures above 280 °C. This oxide is used in silver-oxide batteries. In organic chemistry, silver oxide is used as a mild oxidizing agent. For example, silver oxide oxidizes aldehydes to carboxylic acids. Such reactions often work best when the silver oxide is prepared in situ from silver nitrate and alkali hydroxide.Silver Oxide (Ag2O) is a heavy, brownish black powder, easily reduced by exposure to light. odorless; metallic taste. Soluble in ammonium hydroxide, potassium cyanide solu- tion, nitric acid, and sodium thiosulfate solution; slightly soluble in water; insoluble in alcohol.
Silver Oxide has been known for several centuries, and silver oxide is still widely used in synthetic chemistry, including in novel strategies. Silver oxide has many applications Silver oxide can act as a base – due to the presence of oxide –, as an oxidant – due to silver oxide easy reduction to metallic silver –, as an halogen scavenger – due to the precipitation of silver halides –, or as a source of silver ion, particularly useful for organometallics preparation.Silver oxide is used for polishing and coloring glass yellow. Also, silver oxide is used in purifying drinking water; as a catalyst; and as a germicide and parasiticide. Silver oxide has been used as a base and halide abstracting agent in the synthesis of areneruthenium metallacyclic complexes of dianionic chelating ligands. Silver oxide is a potentially valuable regenerative CO2 sorbent for space applications because silver oxide is a nontoxic solid that reacts with atmospheric CO2 at room temperature to form nontoxic solid silver carbonate.
IUPAC NAME: Silver Oxide; alpha-chaconine; disilver oxid; Ezüst-oxid; Ezüst-oxid; Silver oxide; silver(1+) oxide
TRADE NAME: G-58 C; OleMax types
OTHER NAME: 1302-04-1; 20667-12-3
Silver Oxide is prepared by the reaction of aqueous silver nitrate and hydroxide salts. Ag2O is poorly soluble in all common solvents including water. Silver oxide is however readily soluble in ammonia, leading the Tollens'reagent which possesses a historical importance in the development of organic chemistry. This also illustrates the fact that (as for other metal-based reagents), properties of Ag2O may depend on the formation of complexes in the reaction medium. Other commercially important silver chemicals include silver oxide which is used in batteries and silver cyanide which is used in electroplating.
Mediates monoprotection of symmetrical diols with alkyl halides in good to excellent yield. Silver oxide may be used to mediate the following processes: Selective monoalkylation of symmetric diols in the presence of alkyl halide. Palladium catalyzed cross-coupling of aryl- and alkenylsilanols with organic halides. Palladium-catalyzed reaction of aryl and alkenyl halides with terminal alkynes to form arylated or alkenylated alkynes, respectively. Silver oxide, Ag2O, is made by action of oxygen under pressure on silver at 300 °C, or by precipitation of a silver salt with carbonate-free alkali metal hydroxide; Silver oxide is covalent, each silver atom (in solid Ag2O) having two collinear bonds and each oxygen atom four tetrahedral ones; two such interpenetrating lattices constitute the structure.
Brownish-black cubic crystals density 7.14 g/cm3 at 16°C; begins to decompose around 200°C, decomposition becoming rapid at 250 to 300°C insoluble in water and ethanol soluble in acids and alkalis; sparingly soluble in solutions of caustic alkalis; insoluble in alcohol. As catalyst; in the purification of drinking water; in the glass industry (polishing, coloring glass yellow). Silver oxide is precipitated by mixing solutions of silver nitrate and caustic soda 2AgNO3 + 2NaOH → Ag2O + 2NaNO3 + H2O. Odorless brown-black solid. Sinks in water.
Hydrogen sulfide is rapidly oxidized and may ignite in contact with Silver oxide [Bretherick 1979 p. 977], Mixtures of metal sulfides, gold(III) sulfide, antimony sulfide or mercury (II) sulfide, phosphorus, sulfur, selenium, and selenium disulfide ignite on grinding with the oxide. Ammonia or hydrazine slowly react with Silver oxide forming silver nitride or in the presence of alcohol, silver fulminate may also be produced [Bretherick 1979 p. 203]. Oxidation of magnesium is explosive when warmed with Silver oxide. Fire and explosion risk in contact with organic materials or ammonia. Contact with eyes causes mild irritation. If continued for a long period, ingestion or inhalation of silver compounds can cause permanent discoloration of the skin (argyria). Decomposes into metallic silver and oxygen. If large quantities are involved, the oxygen might increase the intensity of the fire.
A poison by intraperitoneal route. Moderately toxic by ingestion. Flammable by chemical reaction; an oxidizing agent. Explodes in contact with ammonia. Incompatible with CuO, (NH3 + ethanol), (hydrazine + ethanol), CO, HzS, Mg, auric sulfide, Sb sulfide, Hg sulfide, nitroalkanes, Se, S, P, K, Na, NaK, seleninyl chloride. See also SILVER COMPOUNDS. Gray monoclinic or cubic crystals or powder; diamagnetic; semiconductor; density 7.48 g/cm3; decomposes to silver oxide is elements above 100°C; insoluble in water (solubility 27 mg/L at 25°C); soluble in alkalis; decomposes in ammonia solution evolving nitrogen; dissolves in dilute acids with decomposition evolving oxygen; forms a brown solution in concentrated nitric acid, and forms intense green coloration in concentrated sulfuric acid. Silver oxide is used to make silver oxide-zinc alkali batteries. Also, silver oxide is an oxidizing agent. Silver oxide is prepared by reacting silver nitrate with potassium persulfate in the presence of a base.
In the manufacture of silver oxide-zinc alkali batteries. Silver oxide is used as the base in special cases of Suzuki–Miyaura cross-couplings as, for example, in reactions with n-alkylboronic acids ((62)229 and (63)230), including MeB(OH)231,232 —which have been considered as substrates of low nucleophilicity, giving low yields of cross-coupling products under standard conditions.Silver oxide is a highly insoluble thermally stable Silver source suitable for glass, optic and ceramic applications. Silver oxide is a photosensetive fine black powder that decomposes High Purity (99.999%) Silver Oxide (Ag2O)Powderabove 280 °. Oxide compounds are not conductive to electricity.
However, certain perovskite structured oxides are electronically conductive finding application in the cathode of solid oxide fuel cells and oxygen generation systems. They are compounds containing at least one oxygen anion and one metallic cation. They are typically insoluble in aqueous solutions (water) and extremely stable making them useful in ceramic structures as simple as producing clay bowls to advanced electronics and in light weight structural components in aerospace and electrochemical applications such as fuel cells in which they exhibit ionic conductivity. Metal oxide compounds are basicanhydrides and can therefore react with acids and with strong reducing agents in redox reactions. Silver Oxide is also available in pellets, pieces, powder, sputtering targets, tablets, and nanopowder (from American Elements' nanoscale production facilities). Silver Oxide is generally immediately available in most volumes. High purity, submicron and nanopowder forms may be considered.
As a laboratory reagent. To remove Carbon Dioxide from aqueous solutions in laboratory reactions. In pollution control filters. As a precursor to making Silver Powder. ( by heating silver oxide above 280°C ( 536°F ) ) As a component in making Silver Oxide batteries. To remove Chlorine from acid plating baths, and to remove dissolved Chlorine from water. As an Antibacterial agent for concrete ( 1 Lb Silver Oxide per cubic yard of Concrete (4,050 lbs) ). As an Antimicrobial agent in some infection resistant surgical fabric materials
Silver Oxide absorbs CO2 from air when the humidity is > 25%. (Normal air contains 249ppm CO2) While absorbing CO2, Silver Oxide turns into the yellow-greenish Silver Carbonate (Ag2CO3). Silver Carbonate can then be ‘recharged’ back to Silver Oxide by heating Silver Oxide. Silver Carbonate begins to decompose to Silver Oxide as silver oxide approaches 160°C (320°F). Above about 210°C ( 410°F ) the Silver Carbonate completely decomposes to Ag2O, Silver Oxide. In this way, Silver Oxide can be recycled indefinitely as a Carbon Dioxide scrubber. Above about 280°C ( 536°F ) however,
Silver Oxide releases Oxygen to form Silver Powder. (not good here) Mediates monoprotection of symmetrical diols with alkyl halides in good to excellent yield. Selective monoalkylation of symmetric diols in the presence of alkyl halide. Palladium catalyzed cross-coupling of aryl- and alkenylsilanols with organic halides. Palladium-catalyzed reaction of aryl and alkenyl halides with terminal alkynes to form arylated or alkenylated alkynes, respectively. Silver oxide reacts with CO2 present in the atmosphere to afford silver carbonate. Silver oxide is widely used in the preparation of ceramic pigments. Silver oxide participates in the Arndt-Eistert synthesis.
Polishing glass, coloring glass yellow, catalyst, purifying drinking water, lab reagent, carbon dioxide scrubber, and chemical sensors. Silver oxide is used in the preparation of other silver compounds, and silver-oxide batteries. In organic chemistry, silver oxide finds use as an oxidizing agent for aldehyes to produce carboxylic acids. Silver oxide is the chemical compound with the formula Ag2O. Silver oxide is a fine black or dark brown powder that is used to prepare other silver compounds. S 0133 (OTTO) Silver oxide, 99.99% Cas 20667-12-3 - used in the preparation of other silver compounds, and silver-oxide batteries. In organic chemistry, silver oxide finds use as an oxidizing agent for aldehyes to produce carboxylic acids. Silver oxide is used in silver oxide batteries. Silver oxide is used in many reactions as a mild oxidizing agent such as in oxidation reactions of converting aldehydes to carboxylic acids. Silver oxide is used in synthesis of many compounds. Silver oxide is used in preparation of Tollen's reagent as well.
Silver oxide (SILL-ver one OK-side) is an odorless dark brown or black powder with a metallic taste. Silver oxide is used primarily for polishing glass, the purification of water, and coloring glass. Silver oxide is made by reacting silver nitrate (AgNO3) with sodium or potassium hydroxide (NaOH or KOH). The silver oxide settles out as a precipitate that can then be washed and purified. Silver oxide finds limited commercial and industrial application. Silver oxide is used as an ingredient in the manufacture of glass to give a yellowish caste to the glass. Silver oxide is also a component of mixtures used to polish glass, including the glass used in optical lenses.
Silver oxide is also used as a catalyst in certain industrial operations and in some water purification systems. Referring to a solution that consists of some material dissolved in water. A solid material that settles out of a solution, often as the result of a chemical reaction. Silver oxide is a skin, eye, and respiratory irritant that may cause coughing, wheezing, shortness of breath, and pulmonary edema (accumulation of fluid in the lungs). Silver oxide can also cause burning of the eyes and skin. Ingestion can produce burning of the gastrointestinal tract accompanied by nausea, vomiting, and abdominal pain. Long-term exposure to silver oxide can cause argyreia, a bluish-gray discoloration of the skin, eyes, and mucous membranes (the soft tissues lining the breathing and digestive passages).
Silver oxide is a chemical compound. This fine dry powder with a brownish-black color is primarily used in the preparation of other silver compounds. Silver oxide is a three-dimensional polymer (i.e. chemical compound consisting essentially of repeating structural units) and is not readily soluble in most solvents. Although silver oxide hydrolyzes only slightly in water, silver oxide gives the water a distinctive metallic taste. However, silver oxide is soluble in dilute nitric acid and is easily attacked by acids. Like other silver compounds, silver oxide is not light sensitive and decomposes at temperatures above 280 degrees Celsius.
Silver oxide is used as a reagent in laboratory reactions to form various chemical compounds. Silver oxide dissolves in ammonium hydroxide solutions to give soluble derivatives. Also, silver oxide reacts with alkali chloride solutions to yield alkali hydroxide. Silver oxide is often employed in the synthesis of transition metal-carbene complexes (i.e. organometallic compound featuring a divalent organic ligand).Silver oxide readily reacts with ligand precursors to form the corresponding complexes. Silver oxide is very effective in removing (or scrubbing) carbon dioxide from humidified air (humidity greater than 25 percent).
This property is extensively used in nuclear submarines, the international space station and space shuttles. Silver oxide reacts with carbon dioxide in the presence of water to generate silver carbonate. Silver oxide is capable of regenerating all the scrubbed carbon dioxide by prolonged heating, which enables each canister (a perforated metal box that absorbs airborne poisons and irritants) to be recycled about 60 times. Silver oxide is used in the manufacture of filters for gas sensors. This filter helps increase the efficiency of chlorine dioxide detectors to free the gas stream from hydrogen sulfides without producing any unwanted compounds.
Silver oxide acts as a catalyst in the preparation of silver powder. If heated above 280 degrees Celsius, silver oxide is converted into silver powder while releasing oxygen gas as a by-product. Silver oxide and zinc form the main components of a silver oxide battery (also called silver –zinc battery). While silver oxide acts as the positive electrode (cathode), zinc behaves as the negative electrode (anode). Unlike silver oxide is competitor counterparts, a silver oxide battery has higher durability, can handle higher current loads, and is free from thermal runaways and inflammability. Such batteries are used in electronic devices as well as U.S. military and Apollo space programs. Silver oxide has enhanced antimicrobial properties and is often used in the manufacture of some infection-resistant surgical fabric materials and fibrous textile articles. Silver oxide is also used in concrete and in some swimming pools and spas to protect the water from undesired microbes.
Silver oxide nanoparticles are wonderful material and having great potential towards biomedical applications. Silver oxide nanoparticle were synthesized via Chemical Aqueous method and characterized by applying manifold available techniques. X-ray diffraction (XRD) was used for analyzing structural property of nanoparticle crystals, the morphology of synthesized nanoparticles was studied by scanning electron microscope (SEM), elemental analysis of the composition was observed by energy dispersive X-ray spectra (EDXS) and the optical properties was analyzed by the Uv–Vis spectrometer.
Spectroscopic analysis confirmed the spherical morphology of the nanoparticles with the effect of calcined temperature. Phototoxic and cytotoxic effects of grown particles were examined by conducting various relevant experimental techniques on hepatocellular (HepG2 Cell line) model. The obtained results were verified by applying polynomial fit which confirmed the goodness of fit. Silver oxide NPs has unique bio interaction characteristics and physicochemical properties as anticancer agent. This research will be beneficial particularly for cancer therapeutics.
A silver oxide powder that replaces silver powder as a silver conductive paste filler has a specific surface area measured by the BET method is 1.0-25.0 m2/g, average primary particle diameter is 1-50 nm, and average secondary particle diameter is 1-1000 nm. The silver oxide powder is made by preparing a neutralization medium that is an aqueous solution containing one or both of sodium hydroxide and potassium hydroxide in a total amount of 0.5 mole/L or less, simultaneously adding an aqueous solution containing silver salt in an amount of 6.0 mole/L or less and an aqueous solution of at least one of sodium hydroxide and potassium hydroxide to the liquid medium to conduct a neutralization reaction, thereby obtaining a neutralized precipitate, maintaining the liquid at a pH in the range of 12±1.5 during the reaction, and subjecting the precipitate to filtration, washing, and drying.
Silver oxide (Ag2O) has been known for several centuries, and silver oxide is still widely used in synthetic chemistry, including in novel strategies. Ag2O is a black powder that is prepared by the reaction of aqueous silver nitrate and hydroxide salts This reagent has many applications; silver oxide can act as a base – due to the presence of oxide –, as an oxidant – due to silver oxide is easy reduction to metallic silver –, as an halogen scavenger – due to theprecipitation of silver halides –, or as a source of silveron, particularly useful for organometallics preparation.Ag2O is poorly soluble in all common solvents including.
Silver oxide is an oxide of silver. Silver oxide is used to prepare other silver compounds, and in the silver oxide battery. Silver is a metallic element with the chemical symbol Ag and atomic number 47. Silver oxide occurs naturally in silver oxide is pure, free form, as an alloy with gold and other metals, and in minerals such as argentite and chlorargyrite. (5, 6, 8) Silver Oxide, Powder, Reagent is a black or brown chemical compound used to prepare silver compounds. In organic synthesis, silver oxide is used as a mild oxidizing agent. Dark brown or black powder. Silver oxide is used for polishing glass and for coloring glass yellow. Silver oxide has also been used at excavation sites for the treatment of Bronze disease. However, silver oxide is not as effective as Benzotriazole and can leave dark spots on the surface. Silver oxide is used medicinally as a germicide.
It is the process for tinting silver-plated products slightly black and obtaining an antique appearance. If necessary, the coating can be improved by using varnish. Also, the varnish does not have a bad effect on the color. Silver oxide is a white, shiny, precious metallic element with the symbol Ag (the symbol Ag comes from the Latin word argentum) on the periodic table of the elements. Silver oxide is atomic number is 47 and silver oxide is atomic weight is 107.87 grams. Silver oxide has a melting point of 961.9 ° C, a boiling point of 1950 ° C, and a specific gravity of 10.5 g / cm. Silver oxide is an inorganic compound with the chemical formula Ag2O. The force that binds silver oxide is atoms is purely ionic in nature; Therefore, silver oxide consists of an ionic solid in which there is a ratio of two cations + electrostatically interacting with an anion O2-. The oxide anion is caused by the interaction of silver atoms on the O2-surface with oxygen in the environment; just like iron and many other metals. Instead of reddening and splintering a piece of silver or jewelry, silver oxide turns black, which is characteristic of silver oxide.
Silver oxide is an ionic solid. Therefore, there cannot be Ag-O or Ag = O covalent bonds in silver oxide is structure; because if silver oxide were, the properties of this oxide would have changed drastically. At that time Ag ions + I2- live in a ratio of 2: 1 and electrostatic attraction. If the number of spheres is counted, silver oxide will be seen with the naked eye that there are nine silver blue and four red. Repeating the structural unit of the AgO tetrahedron4 surrounded by four other Ag + all black solid is created (ignoring any voids or irregularities that these crystalline arrangements may have). Engraving the surface of the silver bowl in the main image results in a solid that is not only black in color but also has brown or brown hues (top picture).
Powdery black-brown solid (note that although silver oxide is an ionic solid, silver oxide does not have a crystalline appearance). Silver oxide is odorless and gives a metallic taste when mixed with water. 277-300 ° C Absolutely turns solid silver; that is, the liquid oxide possibly decomposes before silver oxide is formed. 1.52 ∙ 10-8 in water at 20 ° C. Therefore, silver oxide is almost insoluble in water. If you look closely at the image of silver oxide is structure, the Ag spheres2 + I2- do not differ almost in size. This results in that only small molecules can pass through the interior of the crystal lattice, making silver oxide insoluble in almost all solvents; except where silver oxide reacts such as bases and acids.
Although silver oxide has been repeatedly said that silver oxide is an ionic compound, some properties, such as silver oxide is low melting point, contradict this statement.Of course, considering the covalent character does not destroy what is explained for silver oxide is structure, since silver oxide would be sufficient to add silver oxide to the structure of Ag. 2 Or a sphere and rod model showing covalent bonds.Likewise, tetrahedral and square planes will be linked by covalent bonds (or ionic covalent) as well as AgO4AgOAg lines.With that in mind, Ag2Or would actually be a polymer. However, silver oxide is recommended to consider silver oxide as an ionic solid of covalent character (the nature of the bond remains a challenge today).
Q represents heat in the equation. This explains why the fire that burns the surface of the oxidized silver bowl turns silver oxide into a silvery glow.Therefore, silver oxide is difficult to assume that silver oxide is Ag.2O (l) as silver oxide will instantly decompose from heat; Unless the pressure is raised too high to get the brown black liquid in question. Studies investigating new and sophisticated uses of silver oxide continue to this day. Dissolve in ammonia, ammonium nitrate and water to form Tollens reagent. This reagent is a useful tool in qualitative analysis in organic chemistry laboratories.
Silver oxide allows determination of the presence of aldehydes in the sample by the formation of a "silver mirror" in the test tube as a positive response. In combination with metallic zinc, Silver oxide forms primary zinc-silver oxide batteries. This is perhaps one of the most common and home uses. Acts as a scrubber, for example absorbing CO. 2. When heated, silver oxide releases trapped gases and can be reused for many times. Due to the antimicrobial properties of silver, Silver oxide is oxide is useful in bioanalysis and soil purification studies. Silver oxide is a mild oxidizing agent that can oxidize aldehydes to carboxylic acids. Silver oxide is also used in the Hofmann reaction (from tertiary amines) and participates in other organic reactions as a reagent or a catalyst.
A silver oxide battery was introduced in 1902 by Junger, who used a cadmium anode. Andre perfected this battery in 1943 using zinc. The cell is made of gray spongy zinc plates and silver oxide as a cathode material. Cellophane or wetted polypropylene is employed as a separator material. High concentrations of KOH are used as an electrolyte for heavy duty and NaOH is used for long reliability. Additions of Ag2O and MnO2 to the cathode mix result in flat discharge conditions. The battery delivers 1.3–1.5 V during discharge. The battery is costly and is used in ballistic missiles and in the button form in digital watches.
The electrolytes of silver oxide batteries are nearly the same as that used in AMBs, and accordingly, the formation scheme of the positive electrode mix is similar to that of AMB. The positive-active material is silver monoxide whose electric conductivity is low, which requires the conductive material to be incorporated. Highly pure graphite powder is the best candidate. In general 3–7 wt% of the graphite powder is mixed with the active material. If some reductive impurity is present in the conductive additive, the positive-active material is reduced by silver oxide during storage, resulting in loss of capacity, in addition, formation of carbon dioxide takes place. The carbon dioxide formed consumes the electrolyte to degenerate battery performance. Therefore, the purity of the graphite is very important.
Alkyldihydroxyboranes react with ammoniacal silver oxide to give alkyl dimers.158 Trialkylboranes react with alkaline silver nitrate either in water or in methanol to undergo similar alkyl coupling reactions159. The alkyl coupling is intermolecular in nature, and an unsymmetrical alkyl dimer may be obtained either from two trialkylboranes or from mixed trialkylboranes . The use of a large excess of an organoborane containing the less expensive of the two alkyl groups is advantageous in maximizing the yield of a mixed alkyl dimer based on the more expensive alkyl group.159b Although the precise mechanism of the reaction is not clear, the observed results are consistent with a radical mechanism involving organosilver intermediates which decompose via alkyl radicals. If the reaction is carried out in CCl4, alkyl chlorides are formed as by-products.
Treatment of boracyclanes, readily obtainable via cyclic hydroboration of dienes, with alkaline silver nitrate produces cycloalkanes.160 Common rings may be obtained in good yields. Even some small and medium rings have been obtained in fair to good yields. Anodic oxidation of trialkylboranes also gives good yields of alkyl dimers.161 Electrolysis of trialkylboranes in acetonitrile162 and nitromethane163 gives homologated nitriles and nitro compounds, respectively.
The design of zinc/silver oxide battery is the same as that of zinc/mercuric oxide button cell, but silver oxide operates better at low temperatures and has a high energy density. The main components of this type of batteries are sintered fine silver oxide (Ag2O) powder (cathode), activated zinc (anode) with mercury as additives to avoid corrosion, sodium hydroxide is used as an electrolyte and semi-permeable ion-exchange membrane is used to separate electrodes. During discharge, the silver oxide is reduced to metallic silver and the zinc metal is converted to zinc oxide as given in Eqs. The overall reaction is given by Eq.
This mixture of ammoniacal silver oxide and sodium hydroxide solution is potentially dangerous, because if kept for a few hours silver oxide deposits an explosive precipitate. This danger was described by Tollens in 1882 but is not generally known now. Prepare the reagent just before use, in the tube to be used for the test, and discard immediately after use, NOT into a container for silver residues. Several earlier references to hazards of storing the reagent before or after use are discussed. On one occasion a violent explosion of the reagent occurred 1 h after preparation and before a precipitate had formed, and on another, an empty but unrinsed test tube exploded when picked up. Attempts to recover silver from a batch of the reagent of indeterminate age caused explosions. One hundred and twenty years on, pre-prepared Tollens reagent is still causing explosions.
Brashear's silvering solution (alkaline ammoniacal silver oxide containing glucose) or residues therefrom should not be kept for more than 2 hours after preparation, since an explosive precipitate forms on standing . The danger of explosion may be avoided by working with dilute silver solutions (0.35M) in the Brashear process, when formation of Ag(NH3)2OH (and explosive AgNH2 and Ag3N therefrom) is minimized. The use of Rochelle salt, rather than caustic alkali, and shielding of solutions from direct sunlight, are also recommended safeguards . Addition of sodium gluconate or tartrate to ammoniacal silver salt—base mixtures inhibits the formation of fulminating silver.
Engineered nanomaterial of zinc, titanium, silver, and silicon oxides can make their way into water resources because of renovations and demolitions of building. The ceramic nature of ZnO and the large surface area of silver oxide is nanoparticles form allows nano-ZnO an abundant use as a pigment, semiconductor especially for sunscreens and nanosensors, UV-absorbers and a reactive catalysts of automobile tail gas treatment. The ceramic zinc oxides also display an antimicrobial property induced by the semiconductors. The nanotoxicity of ZnO is dependent on factors such as chemical composition, concentration, exposure route, nanosize, nanosurface characteristics, dissolution, self-assembly, quantum effects, nanostructural property, aggregation.
Silver Oxide-yl radicals have been generated by silver oxide oxidation of Silver Oxide-ylhy-drazine in various aromatic solvents. The thermal decomposition of Silver Oxide-ylcarbonyl peroxide in aromatic solvents affords thiazole with good yields of 2-arylthiazoles. Silver Oxide peroxide gives fair yields of 4-arylthiazoles but thiazol-5-ylcarbonyl peroxide gives no product indicative of thiazol-5-yl radical formation. The most general way of producing Silver Oxide-yl radicals is the thermal decomposition, in a variety of aromatic solvents, at 0 °C and in the presence of alkali, of 2-thiazole diazonium salts resulting from the aprotic diazotization of the corresponding 2-aminothiazole by an alkyl nitrite, the yield of 2-arylthiazole obtained being around 40%.
The strong electrophilic character of Silver Oxide-yl radicals is shown by their ability to substitute at positions of high π-electron density of the aromatic substrate in which they are generated. In agreement with the theory of polarized radicals, the presence of substituents on heteroatomic free radicals can slightly affect their polarity. Introduction in the 5-position of electron-withdrawing substituents slightly enhances the electrophilic character of Silver Oxide-yl radicals.
Refactory metal oxides of NbO x,WO x,TaO x, and Silver oxide (AgO x) have been studied for a high performance collector. The metal oxide materials were deposited on metal substrates by RF sputtering in the Ar/O 2 gas mixture, in which the partial pressure of O 2 was deliberately set at the lower values in order to sputter in the stoichiometrically oxygen gas short conditions. Work function of the metal oxides was measured by cesium plasma immersion technique. As results, minimum work function values of each oxide materials were obtained as follows, AgO x = 1.25 eV, NbO x = 1.38 eV, WO x = 1.42 eV, TaO x = 1.43 eV. NbO x and AgO x are considered most promising for a collector.
A thermionic converter with a plane parallel type of a polycrystalline W emitter and an AgO x collector, an interelectrode spacing at room temperature 0.1 mm, was set up and the power generation experiments were conducted. The maximum power, 3.9 W/cm 2, 0.6 V, 6.5A/cm 2, was obtained under the unignited mode operation at T E = 1583 K. The barrier index was V B = 1.5 V at T E = 1578 K. Based on the experimental results, a new type of a FGM collector was proposed for a micro-gap thermionic converter.
