c2f6 c3f8 c4f10 c5f12 c6f14 c7f16 c8f18 carbon-dioxide carbon-tetrachloride c-c4f8 cf4 cfc113 cfc114 cfc115 cfc11 cfc12 ch2cl2 ch3ccl3 chcl3 factsheet halon1211 halon1301 halon2402 hcfc141b hcfc142b hcfc22 hfc125 hfc134a hfc143a hfc152a hfc227ea hfc236fa hfc23 hfc245fa hfc32 hfc365mfc hfc4310mee methane methyl-bromide methyl-chloride nf3 nitrous-oxide sf6 so2f2