Physical And Chemical Properties Of Niobium

Niobium, with the chemical symbol "Nb", atomic number 41 and atomic weight 92.90638, belongs to the subgroup V (vanadium group) of the periodic system. It is a lustrous gray metal that is paramagnetic. High-purity niobium metal is highly ductile, but hardens with increasing impurity content. Niobium has a low capture cross-section for thermal neutrons and is therefore of considerable use in the nuclear industry.
Niobium metal is stable at room temperature, oxidizes to a dense oxide film at 200°C, and is resistant to corrosion by molten alkalis and a variety of acids, including aqua regia, hydrochloric, sulfuric, nitric and phosphoric acids.