<unk>  (PFIB) is the perfluorocarbon counterpart of the hydrocarbon isobutene and has the formula (CF3)2C=CF2. An alkene, it is a colorless gas that is notable as a highly toxic perfluoroalkene. Few simple alkenes are as toxic.
Perfluoroisobutene
Triphenylbromoethylene
Perfluorooctanoic acid
Chloroethane
Diiodohydroxyquinoline
Desmethylchlorotrianisene
Triphenylchloroethylene
Phenylsilatrane