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).
HCs are highly flammable, and are the primary components of natural gas and petroleum (fuel). HCs are also useful to manufacturing plastics, solvents, rubbers, and a variety of chemicals used in industrial production.