Nomenclature
Chemistry: IB Diploma Higher Level, topic 3.6.1
Nomenclature of Organic Chemistry
Organic nomenclature follows rules from IUPAC (International Union of Pure and Applied Chemistry).
Stems
- In organic nomenclature, the stem of the name notates the number of carbon atoms in the longest chain.
Suffixes
- Many functional groups can be shown in the name of the compound by adding a suffix.
- To know which suffix needs to be added, we need to consider the class of the organic molecule, which is determined by the functional group present.
Suffixes cont.
- The position of the functional group is notated in the name by placing a number between hyphens.
- Some functional groups can only be placed in one place and therefore there is no need to give a number to show its position.
Prefixes
- Branching of the main carbon chain and additions of some functional groups are notated in the structure’s name by adding a prefix.
- The longest carbon chain can be branched and this can be accommodated in the name by using an alkyl prefix.
- Examples of some molecules with alkyl branches are shown above.
Prefixes cont.
- Halogen substituents in halogenoalkanes are also shown by a prefix in the name of the organic compound.
Test yourself on Nomenclature
Which of these statements is correct?