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Stick model of fluoromethane
Spacefill model of fluoromethane
IUPAC name
Other names
Freon 41

Methyl fluoride
Halocarbon 41

3D model (JSmol)
Abbreviations R41
ECHA InfoCard 100.008.907
EC Number 209-796-6
MeSH Fluoromethane
UN number UN 2454
Molar mass 34.03 g/mol
Appearance Colourless gas with pleasant, ether-like odour at high concentrations.
Density 1.4397 g/L

0.557 g/cm3 (liquid) at saturation pressure at 25 °C

Melting point −137.8 °C (−216.0 °F; 135.3 K) [1]
Boiling point −78.4 °C (−109.1 °F; 194.8 K) [1]
1.66 L/kg (2.295 g/L)
Vapor pressure 3.3 MPa
Extremely Flammable F+
R-phrases (outdated) R12
S-phrases (outdated) S9, S16, S23, S24/25, S26, S28, S33, S36/37/39, S60
NFPA 704
Flammability code 4: Will rapidly or completely vaporize at normal atmospheric pressure and temperature, or is readily dispersed in air and will burn readily. Flash point below 23 °C (73 °F). E.g., propaneHealth code 1: Exposure would cause irritation but only minor residual injury. E.g., turpentineReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogenSpecial hazards (white): no codeNFPA 704 four-colored diamond
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Fluoromethane, also known as methyl fluoride, Freon 41, Halocarbon-41 and HFC-41, is a non-toxic, liquefiable, and flammable gas at standard temperature and pressure. It is made of carbon, hydrogen, and fluorine. The name stems from the fact that it is methane (CH4) with a fluorine atom substituted for one of the hydrogen atoms.


The compound is the lowest mass member of the hydrofluorocarbon (HFC) family, compounds which contain only hydrogen, fluorine, and carbon. These are related to the Chlorofluorocarbon (CFC)s, but since they do not contain chlorine, were not destructive to the ozone layer.[2] However, fluorocarbons are potent greenhouse gasses, and the Kigali Amendment to the Montreal Protocol is an attempt to phase them out due to their contribution to global warming.[3]

It is used in the manufacture of semiconductor and electronic products. In the presence of an RF field fluoromethane will dissociate into fluoride ions that selectively etch silicon compound films (reactive-ion etching). Fluoromethane has an agreeable ether-like odor and is also narcotic in high concentrations. Fluoromethane is highly flammable and burns in air with evolution of highly toxic hydrogen fluoride. The flame is colorless, similar to alcohol.

The C-F bond energy is 552 kJ/mol and its length is 0.139 nm (typically 0.14 nm). Its molecular geometry is tetrahedral.

Its specific heat capacity (Cp) is 38.171 J·mol−1·K−1 at 25 °C. The critical point of fluoromethane is at 44.9 °C (318.1 K) and 6.280 MPa.


  1. ^ a b Record in the GESTIS Substance Database of the Institute for Occupational Safety and Health
  2. ^ Fluoromethane CH3F
  3. ^ "Explainer: hydrofluorocarbons saved the ozone layer, so why are we banning them?".

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