méthane

Méthane, also known as methane (chemical formula CH4), is the simplest alkane and the main component of natural gas. It is colorless, odorless, and highly flammable at room temperature and standard pressure. It has a tetrahedral molecular geometry and a boiling point of −161.5 °C, so it remains a gas under typical conditions. It is lighter than air.

In nature, methane forms in anaerobic environments such as wetlands, ruminant guts, landfills, and rice paddies. It is also released during fossil-fuel extraction, mining, and gas handling. Human activity—agriculture, waste management, and energy production—contributes substantially to atmospheric methane.

Uses and production: Methane is the principal component of natural gas, used for heating, electricity generation, and as a chemical feedstock. It can be converted to hydrogen and carbon monoxide (syngas) by steam reforming, a step in producing hydrogen, methanol, and other chemicals. Methane is odorized in pipeline gas to aid leak detection.

Environmental and safety considerations: Methane is a potent greenhouse gas with a global warming potential higher than carbon dioxide over 100 years. It has an atmospheric lifetime of about a decade. Leaks from production, transport, and use contribute to climate change. It is flammable and forms explosive mixtures with air between about 5% and 15% by volume; proper ventilation and leak detection are essential.