text: *Chlorofluorocarbons (CFCs): when derived from methane and ethane these compounds have the formulae CClF and CClF, where m is nonzero.
  *Hydro-chlorofluorocarbons (HCFCs): when derived from methane and ethane these compounds have the formula CClFH and CClFH, where m, n, x, and y are nonzero.
  * and bromofluorocarbons have formulae similar to the CFCs and HCFCs but also include bromine.
  *Hydrofluorocarbons (HFCs): when derived from methane, ethane, propane, and butane, these compounds have the respective formulae CFH, CFH, CFH, and CFH, where m is nonzero.