Formula Methane and Molecule

Methane Molecule

Methane is a chemical compound with the chemical formula CH4. It is the simplest alkane, and the principal component of natural gas. Methane's bond angles are 109.5 degrees. 

Burning methane in the presence of oxygen produces carbon dioxide and water. The relative abundance of methane makes it an attractive fuel. However, because it is a gas at normal temperature and pressure, methane is difficult to transport from its source. It is generally transported in bulk by pipeline in its natural gas form, or LNG carriers in its liquefied form; few countries transport it by truck.

Methane was discovered and isolated by Alessandro Volta between 1776 and 1778 when studying marsh gas from Lake Maggiore.

Methane is a relatively potent greenhouse gas. Compared with carbon dioxide, it has a high global warming potential of 72 (calculated over a period of 20 years) or 25 (for a time period of 100 years). It has a net lifetime of about 10 years, and is primarily removed by reaction with hydroxyl radicals in the atmosphere, producing carbon dioxide and water.

Formula Methane

Methane also affects the degradation of the ozone layer. The mole fraction of methane in the Earth's atmosphere in 1998 was 1745 nmol/mol (parts per billion, ppb), up from 700 nmol/mol in 1750. By 2008, however, global methane levels, which had stayed mostly flat since 1998, had risen to 1,800 nmol/mol. By 2010, methane levels, at least in the Arctic, were measured at 1850 nmol/mol, a level scientists described as being higher than at any time in the previous 400,000 years. Historically, methane concentrations in the world's atmosphere have ranged between 300 and 400 nmol/mol during glacial periods commonly known as ice ages, and between 600 to 700 nmol/mol during the warm interglacial periods.

In addition, there is a large (but unknown) amount of methane in methane clathrates in the ocean floors. The Earth's crust contains huge amounts of methane. Large amounts of methane are produced anaerobically by methanogenesis. Other sources include mud volcanoes, which are connected with deep geological faults; landfill; and livestock (primarily ruminants) from enteric fermentation.

Methane is not toxic; however, it is extremely flammable and may form explosive mixtures with air. Methane is violently reactive with oxidizers, halogens, and some halogen-containing compounds. Methane is also an asphyxiant and may displace oxygen in an enclosed space. Asphyxia may result if the oxygen concentration is reduced to below 19.5% by displacement. The concentration of methane at which asphyxiation risk becomes significant is much higher than the 5–15% concentration at which flammable or explosive mixtures form. When structures are built on or near landfills, methane off-gas can penetrate the buildings' interiors and expose occupants to significant levels of methane. Some buildings have specially engineered recovery systems below their basements to actively capture such fugitive off-gas and vent it away from the building. An example of this type of system is in the Dakin Building, Brisbane, California.