Atomic number:41

Group numbers:5

Period:5

Electronic configuration:[Kr] 4d⁴ 5s¹

Formal oxidation number:+3 +5

Electronegativities:1.6

Atomic radius / pm:142.9

Relative atomic mass:92.90638 ± 0.00002

 

Niobium was discovered by Charles Hatchett (GB) in 1801. The origin of the name comes from the Greek word Niobe meaning daughter of Tantalus in Greek mythology (tantalum is closely related to niobium in the periodic table). It is a shiny white, soft, ductile metal. Exposed surfaces form oxide film. Niobium occurs in a mineral columbite. It is used in stainless steel alloys for nuclear reactors, jets and missiles. It is used as an alloy with iron and nickel. It can be used in nuclear reactors and is known to be superconductive when alloyed with tin, aluminium or zirconium.

Density / g dm^-3:8570 (293 K)

 7830 (m.p.)

Molar volume / cm³mol^-1:10.84 (293 K)

 11.87 (m.p.)

Electrical resistivity / μΩcm:12.5 (20 °C)

Thermal conductivity / W m^-1K^-1:53.7

Melting point / °C:2477

Boiling point / °C:4744

Heat of fusion / kJ mol^-1:27.2

Heat of vaporization / kJ mol^-1:680.19

Heat of atomization / kJ mol^-1:722.819

1st ionization energy / kJ mol^-1:652.13

2nd ionization energy / kJ mol^-1:1381.68

3rd ionization energy / kJ mol^-1:2416.01

in the atmosphere / ppm:-

in the Earth's crust / ppm:11

in the oceans / ppm:0.00001