Tantalum

Tantalum, chemical element, symbol Ta; for physical constants see Periodic Table. Tantalum was discovered by A.G. Ekeberg in 1802. It occurs in the mineral microlite. It is obtained commercially from colum-bite-tantalite, a mixed oxide with niobium and iron and manganese. The element is prepared by the high-temperature reaction of tantalum (V) oxide with tantalum carbide in a vacuum. Tantalum is a gray, hard, malleable, ductile metal. It is high-melting and resistant to chemical attack. A tantalum carbide-graphite composite is one of the hardest materials ever made. Tantalum and its compounds are used in laboratory apparatus, surgical prostheses, special glasses, electrolytic capacitors, nuclear reactors, aircraft, missiles, and catalysts.