A hydrocarbon is any organic compound composed solely of carbon and Hydrogen. Hydrocarbons include aliphatic compounds, in which the carbon atoms form a chain, and Aromatic Compounds, in which the carbon atoms form stable rings.

The aliphatic group is divided into alkenes (e.g. Methane and propane), alkenes and alkynes, depending on whether the molecules of the compounds contain, respectively, only single bonds, one or more carbon-carbon double bonds, or one or more carbon-carbon triple bonds.

Petroleum distillation yields useful fractions that are hydrocarbon mixtures, e.g. Natural Gas, Gasoline, Kerosene, Home heating oil, Lubricating oils, Paraffin, and asphalt.

Coal Tar is also a source of hydrocarbons. Hydrocarbon derivates contain additional elements, e.g. oxygen, and include Alcohols, aldehydes, ketones, carboxylic acids, and halocarbons.