A hydrocarbon (HC) is a substance that is made of carbon and hydrogen in the gaseous, liquid, or solid phase. The molecular structure of hydrocarbon compounds varies from the simplest to the very heavy and very complex. The first structures are methane, ethane, propane (used for fuel), butane (used in lighters), pentane, hexane, heptane, and octane.
Hydrocarbons can be divided into saturated, unsaturated and aromatic hydrocarbons. Saturated hydrocarbons contain only single bonds. They are called alkanes. Unsaturated hydrocarbons contain double bounds (alkenes) or triple bounds (alkynes).
Although they are highly flammable, HCs may offer advantages as Ozone-Depleting Substance substitutes because they are inexpensive to produce and they have zero ozone depletion potential, very low global warming potential (GWP), and low toxicity.