Methane

Methane
  Carbon, C
  Hydrogen, H
Names
Preferred IUPAC name
Methane
Systematic IUPAC name
Carbane (never recommended)
Other names
  • Carbon tetrahydride
  • Carburetted hydrogen
  • Hydrogen carbide
  • Marsh gas
  • Methyl hydride
  • Natural gas
Identifiers
3D model (JSmol)
3DMet
1718732
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.000.739
EC Number
  • 200-812-7
59
KEGG
MeSH Methane
RTECS number
  • PA1490000
UNII
UN number 1971
  • InChI=1S/CH4/h1H4 Y
    Key: VNWKTOKETHGBQD-UHFFFAOYSA-N Y
  • C
Properties
CH4
Molar mass 16.043 g·mol−1
Appearance Colorless gas
Odor Odorless
Density
  • 0.657 kg/m3 (gas, 25 °C, 1 atm)
  • 0.717 kg/m3 (gas, 0 °C, 1 atm)
  • 422.8 g/L (liquid, −162 °C)
Melting point −182.456 °C (−296.421 °F; 90.694 K)
Boiling point −161.5 °C (−258.7 °F; 111.6 K)
Critical point (T, P) 190.56 K (−82.59 °C; −116.66 °F), 4.5992 MPa (45.391 atm)
22.7 mg/L
Solubility Soluble in ethanol, diethyl ether, benzene, toluene, methanol, acetone and insoluble in water
log P 1.09
14 nmol/(Pa·kg)
Conjugate acid Methanium
Conjugate base Methyl anion
−17.4×10−6 cm3/mol
Structure
Td
Tetrahedral at carbon atom
0 D
Thermochemistry
35.7 J/(K·mol)
186.3 J/(K·mol)
−74.6 kJ/mol
−50.5 kJ/mol
−891 kJ/mol
Hazards
GHS labelling:
Danger
H220
P210
NFPA 704 (fire diamond)
2
4
0
SA
Flash point −188 °C (−306.4 °F; 85.1 K)
537 °C (999 °F; 810 K)
Explosive limits 4.4–17%
Related compounds
Related alkanes
Related compounds
Supplementary data page
Methane (data page)
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
Not to be confused with Ethane or ETHANE. "CH4" redirects here. For other uses, see CH4 (disambiguation).

Methane (US: /ˈmɛθeɪn/ METH-ayn, UK: /ˈmiːθeɪn/ MEE-thayn) is a chemical compound with the chemical formula CH4 (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on Earth makes it an economically attractive fuel, although capturing and storing it poses technical challenges due to its gaseous state under normal conditions for temperature and pressure.

Naturally occurring methane is found both below ground and under the seafloor and is formed by both geological and biological processes. The largest reservoir of methane is under the seafloor in the form of methane clathrates. When methane reaches the surface and the atmosphere, it is known as atmospheric methane.

The Earth's atmospheric methane concentration has increased by about 160% since 1750, with the overwhelming percentage caused by human activity. It accounted for 20% of the total radiative forcing from all of the long-lived and globally mixed greenhouse gases, according to the 2021 Intergovernmental Panel on Climate Change report. Strong, rapid and sustained reductions in methane emissions could limit near-term warming and improve air quality by reducing global surface ozone.

Methane has also been detected on other planets, including Mars, which has implications for astrobiology research.

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