TANTALUM

Tantalum is a rare, hard, and corrosion-resistant chemical element. 
Its chemical symbol is Ta, and its atomic number is 73. 
Tantalum is a shiny, gray metal that belongs to the transition metals group.

CAS No.7440-25-7
Chemical Name:Tantalum
CBNumber:CB3367656
Molecular Formula:Ta
Molecular Weight:180.95
MDL Number:MFCD00011252
MOL File:7440-25-7.mol

Synonyms: TANTALUM POWDER, TANTALUM METAL, TANTALUM WIRE 0.1MM DIA 99.9% (METALS BASIS), Tantal, TANTALUM, TA000300, TA000357, TA000470, TA000280, TA000348.

Tantalum has a very high melting point of about 3,017°C (5,463°F). 
One of its most important properties is its excellent resistance to corrosion. 
Tantalum can withstand many acids and other harsh chemicals, which makes it useful in industrial applications.

Tantalum is widely used in electronics, especially in the production of tantalum capacitors. 
These capacitors are small but can store a relatively large amount of electrical energy, so they are used in devices such as smartphones, computers, cameras, and automotive electronics.

Tantalum is also used in medical applications because Tantalum is generally well tolerated by the human body. 
Tantalum can be used in surgical implants and other medical devices.

Another important use of tantalum is in the aerospace and chemical industries. 
Its resistance to heat and corrosion makes Tantalum suitable for high-temperature components and equipment that must operate in aggressive chemical environments.

Tantalum is usually found in minerals such as tantalite and is often obtained together with niobium, another chemical element with similar properties.
In conclusion, tantalum is an important metal because of its high melting point, excellent corrosion resistance, durability, and usefulness in electronics and medicine.

Definition
A silvery transition element. 
Tantalum is strong, highly resistant to corrosion, and is easily worked. 
Tantalum is used in turbine blades and cutting tools and in surgical and dental work. 
Symbol: Ta; m.p. 2996°C; b.p. 5425 ± 100°C; r.d. 16.654 (20°C); p.n. 73; r.a.m. 180.9479.

Definition
tantalum: Symbol Ta. A heavy bluegrey metallic transition element; a.n. 73; r.a.m. 180.948; r.d. 16.63; m.p. 2996°C; b.p. 5427°C. It is found with niobium in the ore columbite– tantalite (Fe,Mn)(Ta,Nb)2O6. 
Tantalum is extracted by dissolving in hydrofluoric acid, separating the tantalum and niobium fluorides to give K2TaF7, and reduction of this with sodium. 
The element contains the stable isotope tantalum–181 and the long-lived radioactive isotope tantalum–180 (0.012%; half-life >107 years). 
There are several other short-lived isotopes. 
The element is used in certain alloys and in electronic components. 
Tantalum parts are also used in surgery because of the unreactive nature of the metal (e.g. in pins to join bones). 
Chemically, the metal forms a passive oxide layer in air. 
Tantalum forms complexes in the +2, +3, +4, and +5 oxidation states. 
Tantalum was identified in 1802 by Anders Ekeberg (1767–1813) and Ürst isolated in 1820 by Berzelius.

General Description
Tantalum dust is a black odorless powder. 
Mp: 2996°C; bp: approx. 5250°C. Density: 16.65 g cm-3. Insoluble in water. 
Tantalum oxide dust is a white, microcrystalline powder Mp: 1800°C. 
Density: 7.6 g cm-3. 
Insoluble in water. 
The mixture is listed as a toxic inhalation hazard by OHSA.

Properties 
Chemical symbol: Ta
Atomic number: 73
Appearance: Shiny, gray metal
Melting point: 2996 °C (lit.)
Boiling point: 5425 °C (lit.)
Density: 16.69 g/cm3 (lit.)
Bulk density: 500 kg/m3
Vapor pressure: <0.01 mm Hg (537.2 °C)
Storage temp.: No restrictions.
Solubility: Reacts with HF
Form: Wire
Color: Gray to silver
Specific Gravity: 16.6
pH: 7 (20°C in H2O, aqueous suspension)
Flame Color: Blue
Resistivity: 13.5 μΩ-cm, 20°C
Electrical Conductivity: 7.7 × 10⁶ S/m
Water Solubility: Very resistant to attack by acids except HF, resistant to alkali solutions [KIR83]
Thermal Conductivity: 57 W/(m·K)
Specific Heat Capacity: Cp(crystal): 0.14 J/(g·K); Cp(gas): 0.12 J/(g·K), at 25℃
Merck: 13,9143
Exposure limits: ACGIH TLV-TWA: 0.5 ppm (2.5 mg/m3); TLV-CEILING: 2 ppm (Skin)
OSHA PEL-TWA: 5 mg/m3
NIOSH REL-TWA: 5 mg/m3; REL-STEL: 10 mg/m3; REL-Ceiling: 6 ppm (5 mg/m3); REL-IDLH: 30 ppm (250 mg/m3)
Stability: Stable. Powder is very flammable.
InChI: 1S/Ta
InChIKey: GUVRBAGPIYLISA-UHFFFAOYSA-N

Chemical Properties
Tantalum is a blue-gray, ductile metal. 
Tantalum is highly resistant to corrosion though corrosion resistance to strong acids and atmospheric oxygen decreases at increasing temperatures. 
Tantalum is incompatible with strong oxidizers and alkalis.

Uses
Making electronic capacitors
Producing medical implants
Manufacturing high-temperature equipment
Making corrosion-resistant laboratory equipment
Used in aerospace technology
Used in chemical processing equipment
Used in some superalloys

Applications
Tantalum is commonly used in:
Smartphones and computers
Automotive electronics
Aircraft and aerospace equipment
Medical implants and surgical equipment
Chemical and laboratory equipment
Electronic circuits and capacitors.

History
Tantalum was discovered by the Swedish chemist Anders Ekeberg in 1802, although for a long time after his discovery many chemists believed tantalum and niobium were the same element. 
In 1866, Marignac developed a fractional crystallization method for separation of tantalum from niobium. 
Ekeberg named the element in honor of Tantalus, who was Niobe’s father in Greek mythology.
Tantalum is never found in nature in free elemental form. 
The most important mineral is columbite-tantalite (Fe,Mn) (Nb,Ta)2O6. Tantalum also is found in minor quantities in minerals pyrochlore, samarskite, euexenite, and fergusonite. 
The abundance of tantalum in the earth’s crust is estimated as 2 mg/kg.
Tantalum and its alloys have high melting points, high strength and ductility and show excellent resistance to chemical attack. 
Tantalum carbide graphite composite is one of the hardest substances ever made and has a melting point over 6,700°C. 
The pure metal is ductile and can be drawn into fine wire, which is used as filament for evaporating aluminum and other metals.

Uses
Tantalum filaments were used in incandescent lamp bulbs before tungsten replaced them. 
At temperatures below 150°C, tantalum is attacked only by hydrofluoric acid, fluoride ion in acidic solutions, and free sulfur trioxide. 
Tantalum also is attacked, but slowly, by alkalies. 
Tantalum and its alloys, therefore, are used to build reactors, vessels, and cruicibles for preparing and carrying out reactions involving many reactive intermediates. 
The metal and its alloys are used to construct furnace parts, electrolytic capacitors, aircraft and missile parts, chemical process equipment, and nuclear reactors. 
Being nonreactive to body fluids and a nonirritant to body tissues, tantalum is used in making surgical appliances. 
Plate and sheet tantalum are applied in bone repair, foil and wire for nerve repair, and plate, gauge, and sheet for repair of abdominal muscle. 
Tantalum oxide is used to produce optical glasses of high refractive index. 
The oxide film on the metal makes Tantalum a rectifier for converting alternating current to direct current.

Reactions
The most common oxidation state of tantalum is +5 and its aqueous solution chemistry is that of its pentavalent ion Ta5+. 
Ta metal forms a pentavalent oxide, tantalum pentoxide, Ta2O5, on heating with oxygen. 
However, at ordinary temperatures a thin layer of oxide covering the metal surface protects tantalum from most chemical attacks. 
The metal is attacked by hydrofluoric acid below 150°C. 
Tantalum also is dissolved by hot fuming sulfuric acid. 
Tantalum reacts with fluorine and chlorine on heating, forming tantalum pentafluoride, TaF5, and pentachloride, TaCl5, respectively. 
The metal is immune to dilute aqueous alkalies but is attacked slowly by concentrated fused alkalies. 
Tantalum combines with molecular hydrogen above 250°C. 
The hydride formed decomposes on heating above 800°C in vacuum. 
Tantalum forms alloys with several metals.

Discovery
The history of Tantalum and Niobium is a classic case of elemental differentiation in chemistry. 
The story began in 1802 when the Swedish chemist Anders Gustaf Ekeberg analyzed a mineral from Scandinavia. 
Through the process of forming and recrystallizing its acid fluoride salt, Ekeberg discovered a new element, which he named Tantalum, referencing the Greek mythological figure Tantalus.
However, the close chemical similarity between Tantalum and Columbium (the original name for Niobium) led to a period of confusion. 
In 1809, British chemist William Hyde Wollaston compared the oxides of Tantalum and Columbium. 
Despite noting different density values, he mistakenly concluded that the two were an identical material.
This conclusion was later dismissed in 1844 by the German chemist Heinrich Rose. Using chemical methods, Rose successfully demonstrated that they were two distinct elements. 
He named the newly differentiated element "Niobium" and also proposed the name "Pelopium," though only Niobium persisted.
The final confirmation of their distinct identities came in 1864, when Christian Wilhelm Blomstrand and Louis Joseph Troost clearly demonstrated that Tantalum and Niobium were two separate chemical elements and accurately determined the chemical formulas for some of their related compounds.
Regarding the pure metal, the early forms of Tantalum contained significant impurities. 
The first successful isolation of pure Tantalum metal was achieved by Werner von Bolton in 1903.
Historically, the initial method for separating Tantalum from Niobium was the hierarchical crystallization method, discovered by de Marinella in 1866. 
Today, scientists primarily use a more efficient solvent extraction method on solutions containing the fluoride salts of the elements.

Chemical Properties
Tantalum is a refractory metal in Group V-B of the periodic table. 
The pure metal is ductile, steel-blue to gray solid or black, odorless powder.

Physical properties
Tantalum has properties similar to niobium and vanadium above Tantalum in group 5. 
Tantalum is a veryhard and heavy metal with a bluish color when in its rough state, but if polished, it has a silveryshine. 
Tantalum is ductile, meaning it can be drawn into fine wires, and also malleable, meaningit can be hammered and worked into shapes. 
Thin strips and wires of tantalum will ignite inair if exposed to a flame.
Tantalum’s melting point is 2,996°C, which is almost as high as tungsten and rhenium. 
Itboiling point is 5,425°C, and its density is 19.3 g/cm3.

Isotopes
There are 49 isotopes of tantalum. 
Only the isotope Ta-181 is stable andaccounts for 99.988% of the total mass of the element on Earth. Just 0.012% of the element’s mass is contributed by Ta-180, which has a half-life of 1.2×10+15 years and isthus considered naturally stable. 
The remaining 47 isotopes are all artificially producedin nuclear reactions or particle accelerators and have half-lives ranging from a few microsecondsto few days to about two years.

Origin of Name
Tantalum was named after Tantalus, who was the father of Niobe, the queen of Thebes, a city in Greek mythology.

Occurrence
Tantalum is the 51st most abundant element found on Earth. 
Although it is found in afree state, it is usually mixed with other minerals and is obtained by heating tantalum potassiumfluoride or by the electrolysis of melted salts of tantalum. 
Tantalum is mainly obtainedfrom the following ores and minerals: columbite [(Fe, Mn, Mg)(Nb, Ta)2O6]; tantalite [(Fe,Mn)(Ta, Nb)2O6]; and euxenite [(Y, Ca, Er, La, Ce, U, Th)(Nb, Ta, Ti)2O6]. 
Tantalum’s oresare mined in South America, Thailand, Malaysia, Africa, Spain, and Canada. 
The UnitedStates has a few small native deposits but imports most of the tantalum it uses.
Since tantalum and niobium are so similar chemically, a solvent process must be employedto separate them from the common ores. 
They are dissolved in a solvent, resulting in 98% pure niobium oxide being extracted during this part of the process. 
This is followed by 99.5%pure tantalum oxide being extracted in a second solvent process.

Characteristics
Tantalum is almost as chemically inert at room temperatures (it has the ability to resistchemical attacks, including hydrofluoric acid) as are platinum and gold. 
Tantalum is often substitutedfor the more expensive metal platinum, and its inertness makes Tantalum suitable for constructingdental and surgical instruments and artificial joints in the human body.

History
Discovered in 1802 by Ekeberg, but many chemists thought niobium and tantalum were identical elements until Rose, in 1844, and Marignac, in 1866, showed that niobic and tantalic acids were two different acids. 
The early investigators only isolated the impure metal. The first relatively pure ductile tantalum was produced by von Bolton in 1903. 
Tantalum occurs principally in the mineral columbite-tantalite (Fe, Mn)(Nb, Ta)2O6. 
Tantalum ores are found in Australia, Brazil, Rwanda, Zimbabwe, Congo- Kinshasa, Nigeria, and Canada. 
Separation of tantalum from niobium requires several complicated steps. Several methods are used to commercially produce the element, including electrolysis of molten potassium fluorotantalate, reduction of potassium fluorotantalate with sodium, or reacting tantalum carbide with tantalum oxide. 
Thirty-four isotopes and isomers of tantalum are known to exist. 
Natural tantalum contains two isotopes, one of which is radioactive with a very long half-life. 
Tantalum is a gray, heavy, and very hard metal. 
When pure, Tantalum is ductile and can be drawn into fine wire, which is used as a filament for evaporating metals such as aluminum. 
Tantalum is almost completely immune to chemical attack at temperatures below 150°C, and is attacked only by hydrofluoric acid, acidic solutions containing the fluoride ion, and free sulfur trioxide. 
Alkalis attack it only slowly. 
At high temperatures, tantalum becomes much more reactive. 
The element has a melting point exceeded only by tungsten and rhenium. 
Tantalum is used to make a variety of alloys with desirable properties such as high melting point, high strength, good ductility, etc. 
Scientists at Los Alamos have produced a tantalum carbide graphite composite material that is said to be one of the hardest materials ever made. The compound has a melting point of 3738°C. 
Tantalum has good “gettering” ability at high temperatures, and tantalum oxide films are stable and have good rectifying and dielectric properties. 
Tantalum is used to make electrolytic capacitors and vacuum furnace parts, which account for about 60% of its use. 
The metal is also widely used to fabricate chemical process equipment, nuclear reactors, and aircraft and missile parts. 
Tantalum is completely immune to body liquids and is a nonirritating metal. 
Tantalum has, therefore, found wide use in making surgical appliances. 
Tantalum oxide is used to make special glass with a high index of refraction for camera lenses. 
The metal has many other uses. 
The price of (99.9%) tantalum is about $2/g.

Uses
A mixture of tantalum carbide (TaC) and graphite is a very hard material and is used toform the cutting edge of machine tools. 
Tantalum pentoxide (Ta2O5) is dielectric, making ituseful to make capacitors in the electronics industry. 
When mixed with high-quality glass, itimparts a high index of refraction, making it ideal for camera and other types of lenses.
Because of its hardness and noncorrosiveness, tantalum is used to make dental and surgicaltools and implants and artificial joints, pins, and screws. 
The metal does not interactwith human tissues and fluids. 
Since tantalum can be drawn into thin wires, it is used inthe electronics industry, to make smoke detectors, as a getter in vacuum tubes to absorbresidual gases, and as filaments in incandescent lamps. 
Tantalum has many other uses in the electronicsindustry.
The use of tantalum to make miniaturized electrolytic capacitors that store electric chargesin devices such as cell phones and computers is becoming increasingly popular. 
Powderedtantalum is used in the process of sintering to form malleable bars and plates as well as specialelectrodes for the electronics industry.
As a result of their hardness, noncorrosiveness, and ductility, tantalum alloys are used tofabricate parts for nuclear reactors, missiles, and airplanes, and in industries where metal withthese qualities is required.

Uses
Manufacture of capacitors and other electronic components; chemical equipment and corrosion-resistant tools.

Uses
In pen points; analytical weights; apparatus and instruments for chemical, surgical, and dental use instead of platinum, in tantalum capacitors (a type of electrolytic condenser, trademarked "Tantalytic").

Production Methods
Tantalum was identied that tantalum minerals exists in over 70 differentchemicalcompositions.Thoseofgreatesteconomic importance are tantalite, microlite, and wodginite; however, Tantalum is common practice to name any tantalum-containing mineral concentrate as “tantalite”. Tantalum resources are widespread, with the most important known resources being found in Brazil and Australia. 
In mid-2008, the main mining operations were in Australia, Brazil,Canada,Mozambique,andEthiopiaandinmid-2009, in Brazil, Ethiopia, and China, with additional quantities originating in central Africa, Russia, and Southeast Asia. 
There is continued interest in exploration of this element in other countries, primarily in Egypt, Canada, Mozambique, and Saudi Arabia.
The major world mine producers of tantalum in 2010 were Brazil (180 tons), Mozambique (110 tons), Rwanda (100 tons), and Australia (80 tons). Other countries produced around 170 tons, so the total world production of tantalum was approximately 670 tons. The major producers of tantalum mineral concentrates are Australia, Brazil, and Canada.

Production Methods
The first successful industrial process used to extract tantalum and niobium from the tantalite-columbite-containing minerals employed alkali fusion to decompose the ore, acid treatment to remove most of the impurities, and the historic Marignac fractional-crystallization method to separate the tantalum from the niobium and to purify the resulting K2TaF7. 
Most tantalum production now employs recovery of the tantalum and niobium values by dissolution of the ore or ore concentrate in hydrofluoric acid. 
Then the dissolved tantalum and niobium values are selectively stripped from the appropriately acidified aqueous solution and separated from each other in a liquid-liquid extraction process using methyl isobutyl ketone (MIBK) or other suitable organic solvent. 
The resulting purified tantalum-bearing solution is generally treated with potassium fluoride or hydroxide to recover the tantalum in the form of potassium tantalum fluoride, K2TaF7, or with ammonium hydroxide to precipitate tantalum hydroxide, which is subsequently calcined to obtain tantalum pentoxide, Ta2O5. 
Tantalum metal is generally obtained by sodium reduction of K2TaF7, although electrolysis of K2TaF7 and carbon reduction of Ta2O5 in an electric furnace have also been used. 
Tantalum metal can absorb large volumes of hydrogen during heating in a hydrogenbearing atmosphere at an intermediate temperature range (450–700 °C (842-1,292 °F)). 
The hydrogen is readily removed by heating in vacuum at higher temperatures.