Thiol
Thiol is any organosulfur compound of the form (R−SH), where R represents an alkyl or other organic substituent.
(–SH) functional group itself is referred to as either a thiol group or a sulfhydryl group, or a sulfanyl group.
Thiols are the sulfur analogue of alcohols (that is, sulfur takes the place of oxygen in alcohol).
Some Examples

Methanethiol (Commonly: Methyl Mercaptan)

Ethanethiol (Commonly: Ethyl Mercaptan)
