In organic chemistry, a carbonyl group is a functional group composed of a carbon atom double-bonded to an oxygen atom: C=O. It is common to several classes of organic compounds, as part of many larger functional groups. A compound containing a carbonyl group is often referred to as a carbonyl compound.
The remainder of this article concerns itself with the organic chemistry definition of carbonyl, where carbon and oxygen share a double bond.
A carbonyl group characterizes the following types of compounds:
|Compound||Aldehyde||Ketone||Carboxylic acid||Carboxylate Ester||Amide|
|Compound||Enone||Acyl halide||Acid anhydride||Imide|
Note that the most specific labels are usually employed. For example, R(CO)O(CO)R' structures are known as acid anhydride rather than the more generic ester, even though the ester motif is present.