Also called ethene, ethylene is the simplest member of the olefinic hydrocarbon series and one of the most important raw materials of the organic chemical industry. It occurs in both petroleum and natural gas, but the bulk of the industrial material is produced by heating of higher hydrocarbons. Ethylene can be polymerised to the plastic material polyethylene, reacted with oxygen to give ethylene oxide, or with benzene to give ethylbenzene.