Ketones represent the >C=O (carbonyl) grouping (recommendation C-311.1).
- Substitutive nomenclature: they are named as the hydrocarbon with the same number of carbon atoms ending in -one (recommendation C-311.1).
- Radical-functional nomenclature: the names of the radicals attached to the >C=O group, ending in the word ketone, are named in alphabetical order (recommendation C-311.2). When the >C=O group acts as a substituent, it is named as oxo (recommendation R-18.104.22.168).
A number of common names (in parentheses) are preserved, including the following compounds: