Locants arabic numerals

Mono-, di-, and triunsaturated fatty acids are named with Arabic numeral locants for the unsaturated positions and with the suffix -enoic, -adienoic, and -atrienoic acid in place of the -ane ending of the saturated hydrocarbon name, eg, 10,12,14-octadecatrienoic acid. 

Arabic numerals have also been used in this context, but confusion may result when component sugar residues have structural modifications (eg. cha n requiring superscript locant numbers. The present recommendation folio long established usage in glycolipids [21]. 

Arabic numerals are also used as locants in names (see Section IR-2.14.2), and in the following ways. 

Locants are used to indicate the position of a substituent on, or a structural feature within, a parent molecule. The locants can be arabic numerals or letters. 

Arabic numerals are used as locants in the following ways. 

The first part of the descriptor indicates the number of atoms in the main chain. The arabic numerals after the full stop indicate the lengths of the branches cited in priority order. A superscript locant for each branch denotes the atom in the part of the molecule already numbered to which the branch is attached. 

For branching compounds, the parent structure is the longest continuous chain present in the compound. Consider the compound to have been derived from this structure by replacement of hydrogen by various alkyl groups. Arabic number prefixes indicate the carbon to which the alkyl group is attached. Start numbering at whichever end of the parent structure that results in the lowest-numbered locants. The arable prefixes are listed in numerical sequence, separated from each other by commas and from the remainder of the name by a hyphen. 

---