Niobium is a refractory rare metal. Its color is steel-grey and it has the excellent characteristic for big specific gravity (8.6g/cm3), high melting point (2467℃), high boiling point (4740℃), high intensity, fatigue resistance, metamorphose resistance, corrosion resistance, thermal conductivity, superconductivity, unipolar electric conductivity and absorbing gas etc. Niobium and tantalum belong to the same group of the periodic table, they have almost identical chemical properties and symbiose in the niobate and tantalate mineral. The chemists discovered the niobium element and tantalum element in the niobite-tantalite serial minerals at the beginning of 19th century.
In 1801, the English chemist Charles Hatchett discovered a new element when he analyzed mineral, he called the element columbium and the mineral was also named after columbium. In 1844, the German chemist Heinrich Rose announced that he discovered a ‘new’ element, the element has the similar chemical properties with tantalum and is associated with tantalum in nature. Because the tantalum was named according to the personality of the Greek mythology: Tantalus, the ‘new’ element was named after Niobium according to Tantalus’ daughter: Niobe. In 1866, people made sure that columbite and niobium is the same element, so for a long time, the same element had two different name, the American called it columbium with the symbol Cb and the European called it niobium with the symbol Nb. It is not until 1951 that the International Union of Pure and Applied Chemistry (IUPAC) officially adopted ‘niobium’ as the name of the element. But some countries still called columbium, for example, we could find Cb in some American chemical books.
Niobium has a number of important uses for its excellent properties like good corrosion resistance, good cold-workability and good film oxide electric properties, etc. Niobium has the ability of grain refining in steel, it is widely applied to steel industry, electronic industry, spaceflight and aviation, atomic energy, ocean exploitation etc. and is used as alloy steel additive, superconductor material, high-temperature alloy, single crystal oxide, ceramic capacitor etc.
Tantalum and niobium symbiose closely in nature, they have many similar characteristic like physical, chemical, geochemical and mineralogical etc., so they often occur in the same mineral. Minerals that contain niobium often also contain tantalum, they are distinguished just by primary and secondary element. Some mineral form complete isomorphic serial mineral, such as niobite-tantalite serial mineral: Ta2O5<15% calls niobite, Nb2O5<10% calls tantalite, Nb2O5>Ta2O5 calls tantalite-niobite, Ta2O5>Nb2O5 calls niobite-tantalite