Tantalum is a transition metal in Group VB (Group 6) and the 6th period. It has oxidation numbers ranging from 0 to +5, with +5 being common. Other elements in Group VB are vanadium (V) and niobium (Nb). In the solid state, the metal has a body-centered cubic structure.
The three Group VB elements were all discovered at the beginning of the 19th century, although, since the properties of niobium and tantalum are so similar, there was great confusion at first. In 1802 A.G. Ekberg isolated from some Finnish minerals a new element he called tantalum, after Tantalus, a king in Greek mythology. About the same time Charles Hatchett (a very wealthy man who lived in a luxurious mansion) in England examined a yet unstudied mineral, columbite, and isolated the oxide of a new element. He named it columbium in honor of the country of origin (the present United States) of the mineral. (It is said that the mineral was discovered by John Winthrop the Younger, the first governor of Connecticut.) For some time it was thought that tantalum and columbium were the same substance. However, in 1844 H. Rose examined a sample of columbite and showed that in fact tantalum and columbium (now called niobium) were two different - and new - elements.
The chief mineral of Nb and Ta, (Fe,Mn)M2O6 (where M = Nb and Ta), is called columbite or tantalite depending on which predominates, Nb or Ta.
Tantalum has an abundance in the earth's crust of about 1.7 ppm, roughly comparable to that of arsenic and germanium.
Tantalum is a refractory metal (it has a very high melting point, 2996°C), it is very ductile and can be worked into fine wire or thin foil, and it is completely inert to strong acids below their boiling points. Alkalis attack it only slowly. Because it forms a tightly bonded, impervious oxide layer, tantalum is extremely resistant to corrosion. Therefore it is used in chemical plants and other places in heat exchangers.
About 55% of the world's tantalum is used in capacitors and 27% is used as the carbide, TaC, in cutting tools for steels and special alloys.
The metal is completely immune to body fluids and is nonirritating. Therefore, it has found wide use in surgical appliances.
The chief mineral of Nb and Ta, (Fe,Mn)M2O6 (where M = Nb and Ta), is called columbite or tantalite depending on which predominates, Nb or Ta.