Nomenclature of alkanes

  • Structure of the name: The name of an alkane is made up of two parts, a prefix that indicates the number of carbons in the chain followed by the suffix -ane that characterizes this type of compound (meth-ane, eth-ane, prop-ane , but-ane).
  • Choice of parent chain: Find and name the longest chain in the molecule. If the molecule has two or more chains of equal length, the main chain will be the one with the greater number of substituents.

  • Main chain numbering: Number the carbons of the longest chain starting from the end closest to a substituent. If there are two substituents the same distance from each other, alphabetical order is used to decide how to number.

  • Formation of the name: The name of the alkane is written starting with the name of the substituents in alphabetical order, with the respective locators, and then the name of the main chain is added. If a molecule contains more than one substituent of the same type, its name will be preceded by the prefixes di, tri, tetra, etc.

  • Groups with common names: In organic nomenclature there are some groups of atoms that receive common names. Thus, a carbon bonded to two methyls and one hydrogen is called isopropyl. The name tert-butyl is also widely used to designate the group of three methyls attached to the same carbon.