Ethyl Mercaptan

Ethanethiol (EtSH) is an organic compound with the formula CH₃CH₂SH. It consists of an ethyl group, CH₃CH₂, attached to a thiol group, SH. Its structure parallels that of ethanol, but with S instead of O. The presence of S leads to many different properties, most notably the infamous odour of EtSH. Ethanethiol is also more volatile than ethanol due to a diminished ability to engage in hydrogen bonding. Ethanethiol is toxic. It occurs naturally as a minor component of petroleum, and may be added to otherwise odourless gas products such asliquefied petroleum gas (LPG) to help warn of gas leaks. At these concentrations, ethanethiol is not harmful.