Methanethiol

Methanethiol /ˈmɛθnˈθɒl/ (also known as methyl mercaptan) is an organosulfur compound with the chemical formula CH
3
SH
. 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.

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
3D model (JSmol)
3DMet
ChEBI
ChemSpider
ECHA InfoCard 100.000.748
EC Number
  • 200-822-1
KEGG
RTECS number
  • PB4375000
UNII
UN number 1064
  • InChI=1S/CH3SH/c1-2/h2H,1H3 N
    Key: LSDPWZHWYPCBBB-UHFFFAOYSA-N Y
  • InChI=1/CH3SH/c1-2/h2H,1H3
    Key: LSDPWZHWYPCBBB-UHFFFAOYAW
  • SC
Properties
CH3SH
Molar mass 48.11 g·mol1
Appearance colorless gas[1]
Odor Distinctive, like that of rotten cabbage or eggs
Density 0.9 g/mL (liquid at 0°C)[1]
Melting point −123 °C (−189 °F; 150 K)
Boiling point 5.95 °C (42.71 °F; 279.10 K)
2%
Solubility alcohol, ether
Vapor pressure 1.7 atm (20°C)[1]
Acidity (pKa) ~10.4
Hazards
GHS pictograms
GHS Signal word Danger
H220, H331, H410
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 [1]
Explosive limits 3.9%-21.8%[1]
Lethal dose or concentration (LD, LC):
60.67 mg/kg (mammal)[2]
3.3 ppm (mouse, 2 hr)
675 ppm (rat, 4 hr)[2]
NIOSH (US health exposure limits):
PEL (Permissible)
C 10 ppm (20 mg/m3)[1]
REL (Recommended)
C 0.5 ppm (1 mg/m3) [15-minute][1]
IDLH (Immediate danger)
150 ppm[1]
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).
N verify (what is YN ?)
Infobox references

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