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/cm3. Niobium is a lustrous gray metal that is paramagnetic. High-purity niobium metal is highly ductile but hardens as the impurity content increases.
Niobium exhibits superconducting properties at low temperatures. Under standard atmospheric pressure, the superconducting critical transition temperature T of niobium is 9.25K, which is the highest among all metals with superconducting properties. Its magnetic penetration depth is also the highest of all elements. Niobium is one of three elemental Type II superconductors, the others being vanadium and technetium. The purity of niobium metal greatly affects its superconducting properties.
Niobium has a very low capture cross section for thermal neutrons, so it is quite useful in the nuclear industry.
