Bicyclic Molecule - Nomenclature

Nomenclature

Bicyclic molecules have a strict nomenclature. On its simplest level the parent hydrocarbon is the equivalent open-carbon alkane. For bridged compounds, the prefix bicyclo is added, followed by, between brackets, separated by periods, and, in descending order, the number of carbon atoms between each of the bridgeheads. For example in bicycloheptane the carbon frame contains a total of 7 atoms, hence the parent name heptane. This molecule has three bridges having 2, 2 and 1 carbon atoms, hence the prefix bicyclo. For spiro compounds, terms like spiro are used, indicating that there are 3- and 5-membered rings (because the spiro atom itself is not counted) meeting at the spiro atom.