Thial

A thial or thioaldehyde is a functional group in organic chemistry which is similar to an aldehyde, RC(O)H, in which a sulfur (S) atom replaces the oxygen (O) atom of the aldehyde (R represents an alkyl or aryl group). Thioaldehdyes are even more reactive than the thioketones. With sufficient steric bulk, however, stable thioaldehydes can be isolated.

In early work, the existence of thioaldehydes was inferred by trapping processes. For instance the reaction of Fc2P2S4 with benzaldehyde was proposed to form thiobenzaldehyde, which forms a cycloadduct with the thiothiophophine ylides to form a C2PS3 ring.