thiol

CONT: Les thiols constituent un groupe de composés organiques sulfurés, appelés autrefois mercaptans. [...] On utilise leur odeur désagréable et caractéristique en les mélangeant à des gaz toxiques, d'emploi industriel, afin d'en révéler la présence.

CONT: Thiols, formerly called mercaptans, are among the odorous principles in the scent of skunks and of freshly chopped onions; their presence in petroleum and natural gas is objectionable because they have disagreeable odours, interfere with catalysts used in refining processes, and produce sulfur dioxide upon combustion.
CONT: Thiols added to foodstuffs as flavoring substances usually disappear readily because of their volatility and reactivity.