Space-filling models of the methane molecule

Solid methane exists in several modifications. Presently nine are known. The familiar smell of natural gas as used in homes is achieved by the addition of an odorant, usually blends containing tert-butylthiol, as a safety measure. Methane has a boiling point of -161.5 degrees Celsius at a pressure of one atmosphere. As a gas, it is flammable over a range of concentrations in air at standard pressure. The primary chemical reactions of methane are combustion, steam reforming to syngas, and halogenation. In general, methane reactions are difficult to control. Partial oxidation of methane to methanol, a more convenient, liquid fuel, is challenging because the reaction typically progresses all the way to carbon dioxide and water even with an insufficient supply of oxygen. The enzyme methane monooxygenase produces methanol from methane, but cannot be used for industrial-scale reactions. Combustion of methane is a multiple step reaction. Peters four-step chemistry is a systematically reduced four-step chemistry that explains the burning of methane. Methane is used in industrial chemical processes and may be transported as a refrigerated liquid. While leaks from a refrigerated liquid container are initially heavier than air due to the increased density of the cold gas, the gas at ambient temperature is lighter than air. Gas pipelines distribute large amounts of natural gas, of which methane is the principal component. Contributor: Junjie Chen, ORCID: 0000-0001-5055-4309, E-mail address: [e-mail], Department of Energy and Power Engineering, School of Mechanical and Power Engineering, Henan Polytechnic University, 2000 Century Avenue, Jiaozuo, Henan, 454000, P.R. China