Ethenedithione

Ethenedithione or ethylenedithone is an unstable chemical substance with formula S=C=C=S made from carbon and sulfur.

Ethenedithione can exist as a gas at low pressure and high temperature, but is unstable when condensed or under higher pressure.

It can be stabilized as a ligand binding two cobalt atoms.

Other occurrences as a ligand are in TpW(CO)2(C2S2)– and [TpW(CO)2]2Ni(C2S2)2, where Tp is trispyrazolylborate.

Formation
Ethenedithione can be made by the flash vacuum pyrolysis of 2,5-Dithiacyclopentylideneketene.

Also it has been made by dissociative ionization of tetrathiapentalenedione, and then neutralisation of ions produced.

C2S2 is made along with carbon subsulfide and carbon monosulfide, in an electric discharge in carbon disulfide vapour.

Properties
In its ground state it is a triplet state (3Σg−). Ethenedithione can be trapped in a matrix of solid argon without decomposition.

The infrared spectrum contains a prominent line at 1179.3 cm−1 due to asymmetric C=S stretch of the most common isotopes.

Over 60K, ethenedithione polymerises. Possible polymerisation products include polythiene.