Vinylidene chloride and fluoride can be converted to linear polymers polyvinylidene chloride (PVDC) and polyvinylidene fluoride (PVDF).  The polymerization reaction is:
: n CH=CX   →    (CH−CX)
These vinylidene polymers are isomeric with those produced from vinylene monomers.  Thus polyvinylene fluoride from vinylene fluoride (HFC=CHF).