Thiol

In organic chemistry, a thiol (/ˈθaɪɔːl/, /ˈθaɪɒl/) is an organosulfur compound that contains a carbon-bonded sulfhydryl or sulphydryl (–C–SH or R–SH) group (where R represents an alkyl or other organic substituent). Thiols are the sulfur analogue of alcohols (that is, sulfur takes the place of oxygen in the hydroxyl group of an alcohol), and the word is a portmanteau of "thion" + "alcohol," with the first word deriving from Greek θεῖον (theion) = "sulfur". The –SH functional group itself is referred to as either a thiol group or a sulfhydryl group.