These are as primarily {HEAD ~ chlorofluorocarbons}, such as R12 and R22, i.e., {TAIL ~ dichlorodifluoromethane} and chlorodifluoromethane, respectively 
such as
These are as primarily { HEAD ~ chlorofluorocarbons } , such as R12 and R22 , i.e. , { TAIL ~ dichlorodifluoromethane } and chlorodifluoromethane , respectively
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH REL REL OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH