The chemical formula of methane, a greenhouse gas, is CH₄.
The formula shows that each methane molecule contains one carbon atom and four hydrogen atoms. Methane is the simplest alkane and has a tetrahedral shape around its carbon atom, with the four hydrogen atoms arranged in three dimensions rather than lying flat.
Methane is the main component of natural gas and can form through both biological and geological processes. Microorganisms produce it in oxygen-poor environments such as wetlands, landfills, rice fields, and the digestive systems of ruminant animals. It can also be released during fossil-fuel extraction and transport.
A frequent mix-up is confusing methane with carbon dioxide, whose formula is CO₂. Both gases absorb infrared radiation and contribute to the greenhouse effect, but their formulas and structures are different. The subscript 4 in CH₄ is essential: it indicates four hydrogen atoms bonded to every carbon atom in the molecule.