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