Carbonyl fluoride
Structure of carbonyl fluoride
Structure of carbonyl fluoride
Space-filling model of the carbonyl fluoride molecule
Space-filling model of the carbonyl fluoride molecule
Preferred IUPAC name
Carbonyl difluoride
Other names
  • Carbon difluoride oxide
  • Fluoromethanoyl fluoride
  • Fluorophosgene
3D model (JSmol)
ECHA InfoCard 100.005.941 Edit this at Wikidata
EC Number
  • 206-534-2
RTECS number
  • FG6125000
UN number 2417
  • InChI=1S/CF2O/c2-1(3)4 checkY
  • InChI=1/CF2O/c2-1(3)4
  • FC(F)=O
Molar mass 66.007 g·mol−1
Appearance Colorless gas
Odor Pungent and very irritating[1]
Density 2.698 g/L (gas), 1.139 g/cm3 (liquid at melting point)
Melting point −111.26 °C (−168.27 °F; 161.89 K)
Boiling point −84.57 °C (−120.23 °F; 188.58 K)
Vapor pressure 55.4 atm (20°C)[2]
0.95 D
Occupational safety and health (OHS/OSH):
Main hazards
Very toxic, reacts with water to release HF
GHS labelling:
GHS04: Compressed GasGHS05: CorrosiveGHS06: ToxicGHS08: Health hazard
H280, H290, H314, H330, H331, H370
P234, P260, P261, P264, P270, P271, P280, P284, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P307+P311, P310, P311, P320, P321, P363, P390, P403+P233, P404, P405, P410+P403, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 4: Very short exposure could cause death or major residual injury. E.g. VX gasFlammability 0: Will not burn. E.g. waterInstability 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g. white phosphorusSpecial hazard W: Reacts with water in an unusual or dangerous manner. E.g. sodium, sulfuric acid
Flash point Non-flammable
NIOSH (US health exposure limits):
PEL (Permissible)
REL (Recommended)
TWA 2 ppm (5 mg/m3) ST 5 ppm (15 mg/m3)[2]
IDLH (Immediate danger)
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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Carbonyl fluoride is a chemical compound with the formula COF2. It is a carbon oxohalide. This gas, like its analog phosgene, is colourless and highly toxic. The molecule is planar with C2v symmetry, bond lengths of 1.174 Å (C=O) and 1.312 Å (C–F), and an F–C–F bond angle of 108.0°.[3]

Preparation and properties

Carbonyl fluoride is usually produced as a decomposition product of fluorinated hydrocarbons in the thermal decomposition thereof, for example from trifluoromethanol or tetrafluoromethane in the presence of water:

CF4 + H2O → COF2 + 2 HF

Carbonyl fluoride can also be prepared by reaction of phosgene with hydrogen fluoride and the fluorination of carbon monoxide, although the latter tends to result in over-fluorination to carbon tetrafluoride. The fluorination of carbon monoxide with silver difluoride is convenient:

CO + 2 AgF2 → COF2 + 2 AgF

Carbonyl fluoride is unstable in the presence of water, hydrolyzing to carbon dioxide and hydrogen fluoride:[4]

COF2 + H2O → CO2 + 2 HF


Carbonyl fluoride is very toxic with a recommended exposure limit of 2 ppm as an 8-hour time weighted average and a 5 ppm as a short-term (15-minute average) exposure, where 1 ppm = 2.70 mg of carbonyl fluoride per 1 m3 of air.[1]


  1. ^ a b "Carbonyl Fluoride". NIOSH Pocket Guide to Chemical Hazards. CDC Centers for Disease Control and Prevention. Retrieved 2013-09-10.
  2. ^ a b c d e NIOSH Pocket Guide to Chemical Hazards. "#0108". National Institute for Occupational Safety and Health (NIOSH).
  3. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. pp. 304–305. ISBN 978-0-08-037941-8.
  4. ^ M. W. Farlow; E. H. Man; C. W. Tullock (1960). "Carbonyl Fluoride". Inorganic Syntheses. Inorganic Syntheses. Vol. 6. pp. 155–158. doi:10.1002/9780470132371.ch48. ISBN 9780470132371.