thiocarbonyl compound

A thiocarbonyl compound is a chemical compound containing the bivalent radical >CS, where sulfur replaces oxygen in a carbonyl group. This functional group, -C(=S)-, is found in thioaldehydes and thioketones, as well as compounds with nitrogen or oxygen attached to the carbon.123

Many thiocarbonyl compounds are vibrantly colored and highly reactive. This reactivity stems from the carbon-sulfur double bond, where the differing sizes of the carbon (2p) and sulfur (3p) orbitals lead to poor overlap. The simplest thiocarbonyl compound, thioformaldehyde (CH₂=S), is extremely reactive and cannot be isolated, though it exists in low concentrations in the gas phase and has been detected in interstellar space.23

Common examples include carbon disulfide (S=C=S), used in rayon production, and isothiocyanates (R-N=C=S), found in horseradish and mustard. Thioamides, like ethionamide, are used in medicine for tuberculosis treatment.23