Methane (CH4) 6 : the simplest of hydrocarbons and the principal constituent of natural gas. Pure methane has a heating value of 1,1012 Btu per standard cubic foot
United States Department of Agriculture USDA, Glossary of Terms, Washington, DC, USA 2014. http://www.usda.gov/energy/matrix/FindTerms, (Oil - Amer) {780}