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Nitrosyl fluoride
Skeletal formula of nitrosyl fluoride with measurements
Ball and stick model of nitrosyl fluoride
IUPAC name
Nitrosyl fluoride[citation needed]
Other names
Nitrogen oxyfluoride[citation needed]
3D model (JSmol)
Abbreviations NOF[citation needed]
ECHA InfoCard 100.029.230 Edit this at Wikidata
EC Number
  • 232-153-6
  • InChI=1S/FNO/c1-2-3 checkY
  • FN=O
Molar mass 49.0045 g mol−1
Appearance Colourless gas
Density 2.657 mg mL−1(gas) 1.326 g/cm3(liquid)
Melting point −166 °C (−267 °F; 107 K)
Boiling point −72.4 °C (−98.3 °F; 200.8 K)
Related compounds
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Nitrosyl fluoride (NOF) is a covalently bonded nitrosyl compound.

Physical properties

The compound is a colorless gas, with bent molecular shape.[1] The VSEPR model explains this geometry via a lone-pair of electrons on the nitrogen atom.


Nitrosyl fluoride is typically produced by direct reaction of nitric oxide and fluorine, although halogenation with a perfluorinated metal salt is also possible. The compound is a highly reactive fluorinating agent that converts many metals to their fluorides, releasing nitric oxide in the process:

n NOF + M → MFn + n NO

For this reason, aqueous NOF solutions, like aqua regia, are powerful solvents for metals.[1]

Absent an oxidizable metal, NOF reacts with water to form nitrous acid, which then disproportionates to nitric acid:

NOF + H2O → HNO2 + HF
3 HNO2 → HNO3 + 2 NO + H2O

These reactions occur in both acidic and basic solutions.[1]

Nitrosyl fluoride also forms salt-like adducts with Lewis-acidic fluorides; for example, BF3 reacts to give NOBF4. Similarly, the compound nitrosylates compounds with a free proton; thus alcohols convert to nitrites:[1]



Nitrosyl fluoride is used as a solvent and as a fluorinating and nitrating agent in organic synthesis. It has also been proposed as an oxidizer in rocket propellants.[citation needed]


  1. ^ a b c d Greenwood, Norman N.; Earnshaw, Alan (1984). Chemistry of the Elements. Oxford: Pergamon Press. p. 507. ISBN 978-0-08-022057-4.