Freon is the trade name used for a group of chlorofluorocarbons
that are used in refrigeration
, air conditioning
, etc.). The most commonly used are CFC
F) and CFC-12(CCl2
They have been implicated as one of the causes of the ozone layer depletion problem. They are no longer being produced and while it is not illegal to own systems using them it is recommended that these be modified to use an alternative. R-134a is the name of the main US alternative.