<P> CFCs and HCFCs are used in a variety of applications because of their low toxicity, reactivity and flammability . Every permutation of fluorine, chlorine and hydrogen based on methane and ethane has been examined and most have been commercialized . Furthermore, many examples are known for higher numbers of carbon as well as related compounds containing bromine . Uses include refrigerants, blowing agents, propellants in medicinal applications and degreasing solvents . </P> <P> Billions of kilograms of chlorodifluoromethane are produced annually as precursor to tetrafluoroethylene, the monomer that is converted into Teflon . </P> <Ul> <Li> Chlorofluorocarbons (CFCs): when derived from methane and ethane these compounds have the formulae CCl F and C Cl F, where m is nonzero . </Li> <Li> Hydro - chlorofluorocarbons (HCFCs): when derived from methane and ethane these compounds have the formula CCl F H and C Cl F H, where m, n, x, and y are nonzero . </Li> <Li> and bromofluorocarbons have formulae similar to the CFCs and HCFCs but also include bromine . </Li> <Li> Hydrofluorocarbons (HFCs): when derived from methane, ethane, propane, and butane, these compounds have the respective formulae CF H, C F H, C F H, and C F H, where m is nonzero . </Li> </Ul> <Li> Chlorofluorocarbons (CFCs): when derived from methane and ethane these compounds have the formulae CCl F and C Cl F, where m is nonzero . </Li>

Five items in which cfc gas is used