CFCs = Chlorofluorocarbons
CCl3F, or CCl2F2
they are stable, non-flammable, non-toxic chemicals...
it was widely used as the stuff in refrigerators in the past.
but there were some serious problems with this compounds:
when CCl3F escapes into the upper atmosphere, a reaction occurs, one of the Cl atom might "splits" off due to radiation, so, a Cl radical (a single atom) is released.
Cl + O3 --> O2 + ClO
this reaction leads to the destruction of ozone layer.
however, something more serious happens:
ClO + O --> O2 + Cl (radical)
(notice that the oxygen radical comes from O3 <--> O2 + O, ozone is being formed and destroyed by this reversible ractions)
notice that the Cl radical comes back! and its ready to attack again!
it acts as a catalyst in a way! one molecule of Cl radical can destroys tons of ozone molecules.......
well, is it non-stoppable? no, it reactions with some other substances in the atmosphere... one of them is:
ClO + NO2 --> ClONO2
(since ClO and NO2 are both radicals)
and
CH4 + Cl --> HCl + CH3
since this chemical is so dangerous to our atmosphere, it was reduced in production... laws are passed... well, thats not the focus here...
