Compounds have a structure represented by Formula I:CF.sub.2 .dbd.CF--X--R--(X--CF.dbd.CF.sub.2).sub.mwherein R represents an unsubstituted or inertly substituted hydrocarbyl group; each X is independently selected from the group consisting of groups having at least one non-carbon atom between R and --CF.dbd.CF.sub.2 ; and m is an integer of from 1 to about 3. Polymers formed from such compounds are also prepared. The compounds are preferably prepared by a method by a process comprising the steps of:(a) forming a salt having anion corresponding to a compound of Formula II:HX--R--(XH.sub.m); wherein X, R and m are as defined for Formula I:(b) reacting the salt with a 1,2-dihalo-1,1,2,2-tetrafluoroethane wherein the halo groups are iodine, bromine, chlorine or mixtures thereof, at least one halo group being bromine or iodine, to form a compound of Formula III:Z--CF.sub.2 CF.sub.2 --X--R--(X--CF.sub.2 CF.sub.2 --Z).sub.m wherein X, R and m are as defined for Formula I and each Z is independently iodine or bromine;(c) eliminating the halogen atoms represented by Z to form the perfluorovinyl compound represented by Formula I.