niobium (Nb)

niobium cavity resonantor. Image credit: DESY

A niobium cavity resonator, part of a superconducting linear accelerator. Source: DESY.

Niobium (Nb) is a soft, silvery-white, rare metallic element in group VB of the periodic table. Niobium is a transition element. It occurs as columbite (niobium was also formerly known as columbium) and pyrochlore. It was first discovered in 1801.


Niobium is unreactive and corrosion-resistant, and is used in steels, high-temperature alloys, and superconducting alloys (see superconductivity. Being permeable to neutrons, it is also used in nuclear reactors. At high temperatures it reacts with nonmetals to give pentavalent covalent compounds. Its most common isotope is 93Nb (100%).


atomic number 41
relative atomic mass 92.9
relative density 8.57 (20°C)
melting point 2,477°C (4,491°F)
boiling point 4,744°C (8,571°F)