Methane

Names Preferred IUPAC nameSystematic IUPAC nameOther names Identifiers 1718732 ChEBIChEMBLChemSpiderECHA InfoCard100.000.739EC Number59 KEGGMeSHMethaneRTECS numberUNIIUN number1971 Properties CH₄Molar mass16.043 g·mol Appearance Colorless gas OdorOdorless DensityMelting point−182.456 °C (−296.421 °F; 90.694 K) Boiling point−161.49 °C (−258.68 °F; 111.66 K) Critical point (T, P) 190.56 K (−82.59 °C; −116.66 °F), 4.5992 MPa (45.391 atm) 22.7 mg/L SolubilitySoluble in ethanol, diethyl ether, benzene, toluene, methanol, acetone and insoluble in waterlog P1.09 14 nmol/(Pa·kg) Conjugate acidMethaniumConjugate baseMethyl anion−17.4×10 cm/mol Structure T_dTetrahedral at carbon atom 0D 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: DangerH220P210NFPA 704 (fire diamond) Flash point−188 °C (−306.4 °F; 85.1 K) 537 °C (999 °F; 810 K) Explosive limits4.4–17% Related compounds Supplementary data page Methane (data page)

Methane (US: , UK: ) is a chemical compound that has the chemical formulaCH₄ (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 abundance of methane on Earth makes it an economically attractive fuel, although capturing and storing it is difficult because it is a gas at standard temperature and pressure. In the Earth's atmosphere methane is transparent to visible light but absorbs infrared radiation, acting as a greenhouse gas. Methane is an organichydrocarbon, and among the simplest of organic compounds.

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.

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