Dicaesium peroxide

  • Formula: Cs2O2
  • Hill system formula: Cs2O2
  • CAS registry number: [12053-70-2]
  • Formula weight: 297.81
  • Class: oxide
  • Colour: yellow
  • Appearance: crystalline sold
  • Melting point: 590°C
  • Boiling point:
  • Density:

The following are some synonyms of dicaesium peroxide:

  • dicaesium peroxide
  • caesium(I) peroxide
  • cesium(I) peroxide
  • dicesium peroxide

The oxidation number of caesium in dicaesium peroxide is 1.


One way to make caesium peroxide is to react caesium metal in liquid ammonia with with contolled amounts of elemental oxygen.

2Cs(NH3) + O2 → Cs2(O2)

Solid state structure

  • Geometry of caesium:
  • Prototypical structure:

Crystal structure of dicaesium peroxide

Element analysis

The table shows element percentages for Cs2O2 (dicaesium peroxide).

Element %
Cs 89.26
O 10.74

Isotope pattern for Cs2O2

The chart below shows the calculated isotope pattern for the formula Cs2O2 with the most intense ion set to 100%.


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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