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The most common representative is dichlorodifluoromethane (R-12 or Freon-12).
Many CFCs have been widely used as refrigerants, propellants (in aerosol applications), and solvents.
Freon-12, for example, indicates a methane derivative (only two numbers) containing two fluorine atoms (the second 2) and no hydrogen (1-1=0). Another, easier equation that can be applied to get the correct molecular formula of the CFC/R/Freon class compounds is this to take the numbering and add 90 to it.
Thus, methane boils at −161 °C whereas the fluoromethanes boil between −51.7 (CF).In general the density of these compounds correlates with the number of chlorides.CFCs and HCFCs are usually produced by halogen exchange starting from chlorinated methanes and ethanes.The physical properties of CFCs and HCFCs are tunable by changes in the number and identity of the halogen atoms.In general they are volatile, but less so than their parent alkanes.
The CFCs are far less flammable than methane, in part because they contain fewer C-H bonds and in part because, in the case of the chlorides and bromides, the released halides quench the free radicals that sustain flames.