AbstractThe present paper describes the action of dechlorination agents upon hexachloropropene the preparation of decachlorohexadiene‐1,5, of a liquid isomer, probably decachlorohexadiene‐2,4, the cleavage and the cyclisation of both compounds. The compound obtained by cyclisation, a decachloromethylcyclopentene, can be cleaved into carbon tetrachloride and hexachlorocyclopentadi