Bromochlorodifluoromethane

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Bromochlorodifluoromethane
Halon-1211-2D.png Halon-1211-3D-vdW.png
Identifiers
CAS number 353-59-3 YesY
PubChem 9625
ChemSpider 9248 YesY
UNII 91I5X8AJXS YesY
EC number 206-537-9
Jmol-3D images Image 1
Image 2
Properties
Molecular formula CBrClF2
Molar mass 165.36 g/mol
Appearance Colorless gas
Density 1.799 g/cm3
Melting point −159.5 °C
Boiling point −3.7 °C
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 YesY (verify) (what is: YesY/N?)
Infobox references

Bromochlorodifluoromethane, also known by the trade name Halon 1211, or BCF, or Halon 1211 BCF, or Freon 12B1, is a haloalkane with the chemical formula CF2ClBr.

Brominated haloalkanes were first used during World War II as fire extinguisher for aircraft and tanks. Bromochlorodifluoromethane was introduced as an effective gaseous fire suppression agent in the mid 1960s for use around highly valuable materials in places such as museums, mainframe rooms and telecommunication switching centers. They were also widely used in the maritime industries in the engine rooms of ships and also in the transport industry in vehicles. Its efficiency as a fire extinguishing agent has also led it to be the predominant choice of fire extinguishing agent on commercial aircraft and is typically found in cylindrical hand-held canisters. Its advantages as a fire extinguishing agent are that it has lower toxicity than chemicals such as carbon tetrachloride and that since it is a covalently bonded compound, it does not form conductive ions, therefore being usable on electrical equipment.

Ozone depleting substance[edit]

The production of bromochlorodifluoromethane and similar chlorofluorocarbons has been banned in most countries since January 1, 1994 as part of the Montreal Protocol on ozone depleting substances. However, recycling of halon 1211 allows it to remain in use, although parts availability is limited to a few manufacturers and can be an issue. Halon 1211 is still widely used in the United States, despite its high cost, with the US Military being the biggest user, but Europe and Australia have banned its use for all but "critical applications" such as aviation, military, and police use.

The manufacture of UL Listed halon 1211 extinguishers was supposed to cease on October, 2009. The future listing is still in discussion. Halotron I is the replacement extinguishing agent. It takes a larger volume to get the same ratings as 1211 has.

This is a volatile extinguishing agent that should be used only with a breathing apparatus.

See also[edit]

References[edit]

  • George H. Tryon et al., "Fire Protection Handbook Thirteenth Edition 1969", National Fire Protection Association, Boston Massachusetts, 1969, Library of Congress 62-12655, no ISBN.
  • Arthur E. Cote et al., "Fire Protection Handbook Eighteenth Edition", National Fire Protection Association, Quincy, Massachusetts, 1997, ISBN 0-87765-377-1

External links[edit]