Cobalt compounds: dicobalt trioxide

cobalt symbol icon

The cobalt in dicobalt trioxide formally is in the oxidation state 3.

Dicobalt trioxide

  • Formula as often written: Co2O3
  • Hill system formula: Co2O3
  • CAS registry number: [1308-04-9]
  • Formula weight: 165.865
  • Class: oxide


  • dicobalt trioxide
  • cobalt(III) oxide
  • cobalt trioxide

Physical properties

  • Colour: grey-black
  • Appearance: powder
  • Melting point: 895°C (decomposes)
  • Boiling point:
  • Density: 5200 kg m-3


Coming soon...

Element analysis

Element percentages for the elements in dicobalt trioxide
Element %
Co 71.06
O 28.94


This may not be a real compound.

Isotope pattern

What follows is the calculated isotope pattern for the Co2O3 unit with the most intense ion set to 100%.

Formula: Co2O3

mass  %
166 100.0 __________________________________________________
167 0.1
168 0.6


The data on these compounds pages are assembled and adapted from the primary literature and several other sources including the following.

  • R.T. Sanderson in Chemical Periodicity, Reinhold, New York, USA, 1960.
  • N.N. Greenwood and A. Earnshaw in Chemistry of the Elements, 2nd edition, Butterworth, UK, 1997.
  • F.A. Cotton, G. Wilkinson, C.A. Murillo, and M. Bochmann, in Advanced Inorganic Chemistry, John Wiley & Sons, 1999.
  • A.F. Trotman-Dickenson, (ed.) in Comprehensive Inorganic Chemistry, Pergamon, Oxford, UK, 1973.
  • R.W.G. Wyckoff, in Crystal Structures, volume 1, Interscience, John Wiley & Sons, 1963.
  • A.R.West in Basic solid state chemistry Chemistry, John Wiley & Sons, 1999.
  • A.F. Wells in Structural inorganic chemistry, 4th edition, Oxford, UK, 1975.
  • J.D.H. Donnay, (ed.) in Crystal data determinative tables, ACA monograph number 5, American Crystallographic Association, USA, 1963.
  • D.R. Lide, (ed.) in Chemical Rubber Company handbook of chemistry and physics, CRC Press, Boca Raton, Florida, USA, 77th edition, 1996.
  • J.W. Mellor in A comprehensive treatise on inorganic and theoretical chemistry, volumes 1-16, Longmans, London, UK, 1922-1937.
  • J.E. Macintyre (ed.) in Dictionary of inorganic compounds, volumes 1-3, Chapman & Hall, London, UK, 1992.

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cobalt atomic number