Methanethiol

Names Preferred IUPAC nameOther names Identifiers Abbreviations MM
MeSH ChEBIChemSpiderECHA InfoCard100.000.748EC NumberKEGGRTECS numberUNIIUN number1064 Properties CH₄SMolar mass48.10 g·mol Appearance colorless gas OdorDistinctive, like that of rotten cabbage or eggs Density0.9 g/mL (liquid at 0°C) Melting point−123 °C (−189 °F; 150 K) Boiling point5.95 °C (42.71 °F; 279.10 K) 2% Solubilityalcohol, ether Vapor pressure1.7 atm (20°C) Acidity (pK_a) ~10.4 Hazards GHS labelling: DangerH220, H331, H410P210, P261, P271, P273, P304+P340, P311, P321, P377, P381, P391, P403, P403+P233, P405, P501NFPA 704 (fire diamond) Flash point−18 °C; 0 °F; 255 K 364 °C; 687 °F; 637 K Explosive limits3.9%–21.8% Lethal dose or concentration (LD, LC): 60.67 mg/kg (mammal) NIOSH (US health exposure limits): C 10 ppm (20 mg/m) C 0.5 ppm (1 mg/m) [15-minute] 150 ppm Related compounds

Methanethiol ( ), also called methyl mercaptan, is an organosulfur compound with the chemical formulaCH₃SH. It is a colorless flammable gas with a distinctive putrid smell. In small amounts, it is pervasive in nature and found in certain foods, such as some nuts and cheese. It contributes to many odors, including the emissions from pulp mills, bad breath, and flatus. Methanethiol is the simplest thiol and is sometimes abbreviated as MeSH.