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|Atomic Number:||73||Atomic Symbol:||Ta|
|Atomic Weight:||180.9479||Electron Configuration:||2-8-18-32-11-2|
|Melting Point:||2996oC||Boiling Point:||5425oC|
|Description:||Rare gray metal with a high melting point.|
|Uses:||Used in metal alloys. Tantalum pentoxide is used in capacitors and
in camera lenses to increase refracting power
History(Gr. Tantalos, mythological character, father of Niobe)
Discovered in 1802 by Ekeberg, but many chemists thought niobium and tantalum
were identical elements until Rowe 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.
- Tantalum ores are found in Australia, Brazil, Mozambique, Thailand,
Portugal, Nigeria, Zaire, 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, recduction of potassium
fluorotantalate with sodium, or reactng tantalum carbide with tantalum oxide.
IsotopesTwenty five isotopes of tantalum are known to exist. Natural
tantalum contains two isotopes.
- Tantalum is a gray, heavy, and very hard metal.
- When pure, it 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 150C, 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, which is said to be one of the hardest materials ever made.
- The compound has a melting point of 3738C.
- Tantalum has a 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
- It has, therefore, found wide use in making surgical appliances.
- Tantalum oxide is used to make special glass with high index of refraction
for camera lenses.
- The metal has many other uses.
CostsThe price of (99.9%) tantalum in Dec. 1988 was about $50/oz.