Tantalum, one of the transition elements, is a white, ductile, malleable metallic element. Tantalum was discovered in its pure form in 1820 by Baron Jons Jakob Berzelious (the Swedish chemist), who heated potassium tantalifluoride with excess potassium. Tantalum occurs mainly in the mineral tantalite and ranks about 53rd among the elements in abundance in the earth's crust. The main deposits of the tantalum occur in Australia and Scandinavia.
Tantalum is a refractory metal, falling between tungsten and molybdenum in terms of melting point (5425 F). Tantalum's corrosion resistance is excellent in a wide range of severe environments. The metal develops an oxide film on exposure, which acts as a barrier to further corrosion. The corrosion resistance of tantalum is often compared to that of glass.
Other Rare Metal: Titanium Zirconium Nickel
