Oxygen: oxygen difluoride

oxygen difluoride is known by the following synonyms:

  • oxygen difluoride
  • oxygen(II) fluoride
  • difluorine monoxide
  • fluorine oxide
  • oxygen fluoride

The oxidation number of oxygen in oxygen difluoride is 2.

  • Formula: OF2
  • Hill system formula: F2O1
  • CAS registry number: [7783-41-7]
  • Formula weight: 53.996
  • Class: fluoride
  • Colour: colourless
  • Appearance: gas
  • Melting point: -224°C
  • Boiling point: -145°C
  • Density: 2.26 kg dm-3 (gas)


2NaOH + 2F2 → OF2 + 2NaF + H2O

The reaction between fluorine gas and a dilute solution of sodium hydroxide in water results in oxygen fluoride. The product gas also contains oxygen. When pure, oxygen fluoride has a melting point of -223.8°C and boils at -144.8°C. It is soluble to some extent in water.

Solid state structure

  • Geometry of oxygen:
  • Prototypical structure:

Crystal structure of oxygen difluoride

Element analysis

Element percentages in oxygen difluoride
Element %
F 70.37
O 29.63

Isotope pattern for OF2

THe chart below shows the calculated isotope pattern for the formula OF2 with the most intense ion set to 100%.


Coming soon...


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.

WebElements Shop

You can buy periodic table posters, mugs, T-shirts, fridge magnets, games, molecular models, and more at the WebElements shop