A carboxyl group is a functional group consisting of a carbon atom double-bonded to an oxygen atom and single-bonded to a hydroxyl group (-COOH). It is characteristic of carboxylic acids, giving these compounds their acidic properties.
Related terms
Carboxylic acid: Organic compounds containing one or more carboxyl groups that release hydrogen ions in solution, making them acidic.
Functional group: A specific grouping of atoms within molecules that is responsible for the characteristic chemical reactions of those molecules.
Hydrophilicity: The tendency of a molecule or part thereof to interact favorably with water molecules; carboxyl groups increase a molecule's hydrophilicity