Key information
Atomic number: 
Atomic weight: 
8900 kg/m³
Boiling point: 
3173.16° K
Melting point: 
1768.16° K
Heat vapour: 
389.45 kJ/mol
Heat fusion: 
15.24 kJ/mol
Thermal conductivity: 
16 W/m/K
Specific heat capacity: 
67 J/kg/K

The name Cobalt was taken from a mineral used for the production of a blue colour in glass. In 1735 Georg Brandt (1694-1768) identified some properties of cobalt.

Cobalt is a strategic metal with very important applications, including those requiring heat-resistant materials such as jet engines. The major source of cobalt is as a by-product of copper refining although it can also be obtained as a by-product of nickel and lead.

Cobalt(III) complexes display a range of colours:

  • [CoF6]3- - Green
  • [Co(NH3)5Cl]2+ - Violet
  • [Co(H2O)6]3+ - Blue
  • [Co(NH3)5(H2O]3+ - Red
  • [Co(NH3)6]3+ - Yellow-orange
  • [Co(CN6]3- - Tail of absorption band in visible spectrum is yellow
Electron Shell: 
Amazon Books
Image of The Last Sorcerers: The Path from Alchemy to the Periodic Table
Author: National Academy of Sciences, Richard Morris
Publisher: Henry (Joseph) Press (2003)
Binding: Hardcover, 294 pages