Niobium and Tantalum
Niobium (Nb) belongs to Group V of the Periodic Table (Fig. 1.1). Niobium is a comparatively rare element, its content in the Earth’s crust averaging 0.001%. As a rule, it is accompanied by tantalum (Ta) in ores. Columbite (mineral of niobium) was named after Columbia in America, the place of origin of the mineral from which the metal was isolated in 1802. Forty years later, what was thought to be a new element was discovered and named niobium, but further research revealed that niobium and columbium were one and the same element. In Europe the element is still called niobium, whilst in America it is known as columbium.