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Oxygen difluoride

Oxygen difluoride
Other names difluorine monoxide
fluorine monoxide
oxygen difluoride
oxygen fluoride
hypofluorous anhydride
CAS number [7783-41-7]
Molecular formula OF2
Molar mass 53.9962 g mol−1
Melting point

−224 °C

Boiling point

−145 °C

Solubility in other solvents 68 mL gaseous OF2 in 1 L (0 °C)[1]
Std enthalpy of
24.5 kJ mol−1
Related Compounds
Related compounds O2F2
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

Oxygen difluoride is the chemical compound with the formula OF2. As predicted by VSEPR theory, the molecule adopts a bent structure like H2O, but it has very different properties, being a strong oxidant.



Oxygen difluoride was first reported in 1929; it was obtained by the electrolysis of molten potassium fluoride and hydrofluoric acid containing small quantities of water.[2][3] The modern preparation entails the reaction of fluorine with a dilute aqueous solution of sodium hydroxide:

2F2 + 2NaOH → OF2 + 2NaF + H2O


Its powerful oxidizing properties are suggested by the oxidation number of +2 for the oxygen atom, which is unusual. Above 200 °C, OF2 decomposes to oxygen and fluorine via a radical mechanism.

OF2 reacts with many metals to yield oxides and fluorides. Nonmetals also react: phosphorus reacts with OF2 to form PF5 and POF3; sulfur gives SO2 and SF4; and unusually for a noble gas, xenon reacts, yielding XeF4 and xenon oxyfluorides.

Oxygen difluoride reacts very slowly with water to form hydrofluoric acid:

OF2(aq) + H2O(aq) → 2HF(aq) + O2(g)

Popular culture

In Robert L. Forward's science fiction novel Camelot 30K, oxygen difluoride was used as a biochemical solvent by fictional life forms living in the solar system's Kuiper belt.


OF2 is a dangerous chemical, as is the case for any strongly oxidizing gas.


  1. ^ Yost, D. M. "Oxygen Fluoride" Inorganic Syntheses, 1939 volume, 1, pages 109-111.
  2. ^ Lebeau, P.; Damiens, A. "A New Method for the Preparation of the Fluorine Oxide”Compt. rend. 1929, volume 188, 1253-5.
  3. ^ Lebeau, P.; Damiens, A. "The Existence of an Oxygen Compound of Fluorine"Compt. rend. 1927, volume 185, pages 652-4.
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Oxygen_difluoride". A list of authors is available in Wikipedia.
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