Thioketenes are organosulfur compounds analogous to ketenes with the general formula R2C=C=S, where R is alkyl or aryl. Thioketene (ethenone) 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.[1]
Bis(trifluoromethyl)ketene ((CF3)2C=C=S) is a rare example of a stable thioketene.[2] Another stable thioketene is carbon subsulfide (S=C=C=C=S).