Saturated vs. unsaturated hydrocarbons

A hydrocarbon is saturated if it contains no double or triple bonds. If either of these is present in a compound, this will make it unsaturated. Figure 1 shows a visual representation of this principle.

Examples of saturated and unsaturated hydrocarbons. A saturated hydrocarbon is called an alkane and they contain carbon carbon single bonds. Butane, C H 3, C H 2, C H 2, C H 3, is an alkane. There are two types of unsaturated hydrocarbons, alkenes, and alkynes. An alkene contains a carbon carbon double bond. Ethene, C H 2, C H 2, is an alkene. An alkyne contains a carbon carbon triple bond. Propyne, C H, C, C H 3, is an alkyne.

Figure 1. Overview of saturated vs. unsaturated compounds.

The molecular formula of a non-cyclic alkane will follow this rule for the number of carbons and hydrogens: CnH2n+2.

Non-cyclic alkenes follow this rule: CnH2n.

Non-cyclic alkynes follow this rule: CnH2n-2.