Abstract Hexafluorobuta-1, 3-diene and hexafluorocyclobutene interact with elemental sulphur under conditions of mutual conversion (⩾ 280 C) to give the same products, hexafluoro-3, 6-dihydro-1, 2-dithiine (1), hexafluorothiolene-3 (2) and hexafluorothiolanethione (3). The product composition and ratio depend on the reaction conditions. Dithiine 1 and thiolene 2 were formed in competitive reactions. Their thermal ...