Niobium is a metal element. Chemical symbol Nb, atomic number 41, atomic weight 92.90638, belongs to the periodic system V B family. In 1801, C. Hatchet of England separated an oxide of a new element from niobium iron ore and named it columbium. Niobium is a gray-white metal with a melting point of 2468 C, a boiling point of 4742 C and a density of 8.57g/cm gong. Niobium is a glossy gray metal with paramagnetism and belongs to five families on the periodic table of elements. The ductility of high purity niobium metal is higher, but it will harden with the increase of impurity content. Niobium has a very low capture cross section for thermal neutrons, so it is quite useful in nuclear industry.