Methanethiol

Methanethiol
Ball-and-stick model of the methanethiol molecule	Space-filling model of the methanethiol molecule
Names
	Preferred IUPAC name Methanethiol
	Other names Methyl mercaptan; Mercaptomethane; Methiol; Thiomethyl alcohol/Thiomethanol; Methylthiol
Identifiers
CAS Number	74-93-1 ;
3D model (JSmol)	Interactive image;
3DMet	B00105;
ChEBI	CHEBI:16007 ;
ChemSpider	855 [chemspiders];
ECHA InfoCard	100.000.748
EC Number	200-822-1;
KEGG	C00409 ;
PubChem CID	878;
RTECS number	PB4375000;
UNII	2X8406WW9I ;
UN number	1064
CompTox Dashboard (EPA)	DTXSID5026382;
	InChI InChI=1S/CH3SH/c1-2/h2H,1H3 Key: LSDPWZHWYPCBBB-UHFFFAOYSA-N ; InChI=1/CH3SH/c1-2/h2H,1H3 Key: LSDPWZHWYPCBBB-UHFFFAOYAW;
	SMILES SC;
Properties
Chemical formula	CH3SH
Molar mass	48.11 g·mol−1
Appearance	colorless gas
Odor	Distinctive, like that of rotten cabbage or eggs
Density	0.9 g/mL (liquid at 0°C)
Melting point	−123 °C (−189 °F; 150 K)
Boiling point	5.95 °C (42.71 °F; 279.10 K)
Solubility in water	2%
Solubility	alcohol, ether
Vapor pressure	1.7 atm (20°C)
Acidity (pKa)	~10.4
Hazards
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H220, H331, H410
Precautionary statements	P210, P261, P271, P273, P304+P340, P311, P321, P377, P381, P391, P403, P403+P233, P405, P501
NFPA 704 (fire diamond)	4 4 1
Flash point	−18 °C; 0 °F; 255 K
Autoignition; temperature	364 °C; 687 °F; 637 K
Explosive limits	3.9%-21.8%
	Lethal dose or concentration (LD, LC):
LD50 (median dose)	60.67 mg/kg (mammal)
LC50 (median concentration)	3.3 ppm (mouse, 2 hr); 675 ppm (rat, 4 hr)
	NIOSH (US health exposure limits):
PEL (Permissible)	C 10 ppm (20 mg/m3)
REL (Recommended)	C 0.5 ppm (1 mg/m3) [15-minute]
IDLH (Immediate danger)	150 ppm
Related compounds
Related compounds	Ethanethiol Hydrogen sulfide
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Methanethiol /ˌmɛθ.eɪn.ˈθaɪ.ɒl/ (also known as methyl mercaptan) is an organosulfur compound with the chemical formula CH
₃SH. It is a colorless gas with a distinctive putrid smell. It is a natural substance found in the blood, brain and feces of animals (including humans), as well as in plant tissues. It also occurs naturally in certain foods, such as some nuts and cheese. It is one of the chemical compounds responsible for bad breath and the smell of flatus. Methanethiol is the simplest thiol and is sometimes abbreviated as MeSH. It is very flammable.

^ ^a ^b ^c ^d ^e ^f ^g ^h NIOSH Pocket Guide to Chemical Hazards. "#0425". National Institute for Occupational Safety and Health (NIOSH).
^ ^a ^b "Methyl mercaptan". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
^ "Sigma Aldrich Methanethiol SDS". Sigma Aldrich. Millipore Sigma. Retrieved Nov 1, 2022.

[PGCH-1] ^ ^a ^b ^c ^d ^e ^f ^g ^h NIOSH Pocket Guide to Chemical Hazards. "#0425". National Institute for Occupational Safety and Health (NIOSH).

[IDLH-2] "Methyl mercaptan". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).

[3] "Sigma Aldrich Methanethiol SDS". Sigma Aldrich. Millipore Sigma. Retrieved Nov 1, 2022.

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