Wiktionary
n. (context organic chemistry English) (alternative form of episulphide English)
Wikipedia
Episulfides are a class of organic compounds that contain a saturated heterocyclic ring consisting of two carbon atoms and one sulfur atom. It is the sulfur analogue of an epoxide or aziridine. They are also known as thiiranes, olefin sulfides, thioalkylene oxides, and thiacyclopropanes.
The parent episulfide is thiirane. Most preparations of episulfides utilize a two-step method, converting an olefin to an epoxide before its conversion to the episulfide using either thiocyanate or thiourea. Common uses of episulfides in both academic and industrial settings most often involve their use as monomers in polymerization reactions.