A carbonyl group is characterized by a carbon atom double-bonded to an oxygen atom (C=O). It's found in many types of organic compounds including aldehydes, ketones, carboxylic acids, and esters.
An organic compound where the carbonyl group is bonded to two other carbon atoms.
Ester: An organic compound where the carbonyl group is next to -O- (oxygen), forming R-COO-R' structure.
Amide: An organic compound where the carbonyl group is linked to nitrogen (N).