Niobium

Niobium , element symbol: Nb, atomic number 41, is a group VB metal. Niobium has a density of 8.57 g/cm³, a melting point of 2477°C and a boiling point of 4744°C . Niobium is a silver-gray, soft and ductile rare high melting point metal. At room temperature, niobium does not react with air and does not oxidize completely when red hot in oxygen. At high temperatures niobium can be directly chemically synthesized with sulfur, nitrogen and carbon. Niobium does not react with inorganic acids or bases and is insoluble in aqua regia, but is soluble in hydrofluoric acid. The content of niobium in the earth's crust is 20 ppm, and the distribution of niobium resources is relatively concentrated. Because of its good superconductivity, high melting point, corrosion resistance and wear resistance, niobium is widely used in the fields of steel, superconducting materials, aerospace and atomic energy.