Thioketene

Thioketenes are organosulfur compounds analogous to ketenes with the general formula R₂C=C=S, where R is alkyl or aryl. Thioketene (ethenthione) is also the name of the compound CH₂=C=S, which is the simplest thioketene. Thioketenes are reactive, tending to polymerize. Some thioketenes are produced as transient species upon pyrolysis of 1,2,3-thiadiazoles.

Bis(trifluoromethyl)thioketene ((CF₃)₂C=C=S) is a rare example of a stable thioketene. Another stable thioketene is carbon subsulfide (S=C=C=C=S).