Mercaptan (thing)

Ethyl mercaptan, CH₃CH₂SH, is the additive most often used to add odor to natural gas. Mercaptans are particularly suited to giving the colorless, odorless natural gas an odor because of mercaptans' very low threshold of detectability by the human nose. Parts per billion of mercaptans are easily detectable by smell. This ensures that even heavily diluted natural gas will be easily detected.

Mercaptans are known as thiols in modern chemical language. This more accurately describes them as alcohol analogs with sulfur replacing oxygen, and brings the nomenclature together (thioethers are R-S-R', thioesters are R(CO)SR'). No one ever said mercaptoether.