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Niobium (Nb)

Niobium is a chemical element of the periodic table with chemical symbol Nb and atomic number 41 with an atomic weight of 92.9064 u and is classed as transition metal and is part of group 5 (vanadium group). Niobium is solid at room temperature.

Niobium in the periodic table

Atomic number41
Group5 (Vanadium group)
ClassificationTransition Metal
AppearanceGray metallic, bluish when oxidized
Color Gray
Number of protons41 p+
Number of neutrons52 n0
Number of electrons41 e-
From Wikipedia, the free encyclopediaNiobium, formerly columbium, is a chemical element with symbol Nb (formerly Cb) and atomic number 41. It is a soft, grey, ductile transition metal, which is often found in the pyrochlore mineral, the main commercial source for niobium, and columbite. The name comes from Greek mythology:Niobe, daughter of Tantalus since it is so similar to tantalum.

Physical properties

Phase at STPSolid
Density8.57 g/cm3
Atomic weight92.9064 u

Thermal properties

Melting point2750 K
2476.85 °C
4490.33 °F
Boiling point5017 K
4743.85 °C
8570.93 °F
Heat of vaporization690.1 kJ/mol

Atomic properties

Electronegativity (Pauling Scale)1.6
Electron affinity88.516 kJ/mol
Oxidation states−3, −1, 0, +1, +2, +3, +4, +5
(a mildly acidic oxide)
Ionization energies
  1. 652.1 kJ/mol
  2. 1380 kJ/mol
  3. 2416 kJ/mol
  4. 3700 kJ/mol
  5. 4877 kJ/mol
  6. 9847 kJ/mol
  7. 12100 kJ/mol

Electron configuration for niobium

Electron configuration
Shorthand configuration
[Kr] 4d4 5s1
Electron configuration
Full configuration
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d4 5s1
Electron configuration chart
Electrons per shell2, 8, 18, 12, 1
Valence electrons 5
Valency electrons 3,5
Bohr model
NiobiumElectron shell for Niobium, created by Injosoft ABNb
Figure: Shell diagram of Niobium (Nb) atom.
Orbital Diagram

The history of Niobium

DiscoveryCharles Hatchett (1801)
First isolationChristian Wilhelm Blomstrand (1864)
Recognized as a distinct element byHeinrich Rose (1844)
Discovery of niobium
Niobium was identified by English chemist Charles Hatchett in 1801. He found a new element in a mineral sample that had been sent to England from Connecticut, United States in 1734 by John Winthrop F.R.S. (grandson of John Winthrop the Younger) and named the mineral columbite and the new element columbium after Columbia, the poetic name for the United States. In 1809, English chemist William Hyde Wollaston wrongly concluded that tantalum and columbium were identical. German chemist Heinrich Rose determined in 1846 that tantalum ores contain a second element, which he named niobium. In 1864 and 1865, a series of scientific findings clarified that niobium and columbium were the same element (as distinguished from tantalum), and for a century both names were used interchangeably. Niobium was officially adopted as the name of the element in 1949, but the name columbium remains in current use in metallurgy in the United States.


List of unique identifiers for Niobium in various chemical registry databases
CAS Number7440-03-1
ChemSpider ID22378
EC number231-113-5
PubChem CID Number23936