Chlorofluorocarbons (or CFCs are as the name suggests materials that are composed of chlorine and fluorine (halogens)combined with carbon. They are readily condensed gases at room temperature and pressure. They are useful in several applications because of their inert nature and the relative ease with which they can be evaporated and condensed.

  • Halon is used used as a fire extinguisher gas in computer systems because it is non-conductive (unlike water), does not mess up systems (unlike powder), and does not scramble magnetic information (unlike carbon dioxide).
  • Freon was used for a very long time as the primary refrigerant in most systems.
  • CFCs were also used as the primary propellant in most aerosol cans as they did not react with the active ingredients.

Unfortunately it has been discovered that they are one of the primary gases that attack the ozone layer (protects the Earth from excessive ultraviolet irradiation). Due to their relative inactivity they also persist in the environment for a considerable period of time. Nowadays there is a major push to replace them with other more environmentally friendly materials.