Written by the Fiveable Content Team • Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 exam•Written by the Fiveable Content Team • Last updated September 2025
Definition
A hydroxyl group is a functional group consisting of one oxygen atom covalently bonded to one hydrogen atom (-OH). It makes a molecule polar and increases its ability to form hydrogen bonds.
Related terms
Alcohol: This is an organic compound that contains one or more hydroxyl groups attached to a carbon atom.
Phenol: This is an aromatic compound that contains a hydroxyl group directly bonded to an aromatic ring, much like a charm on a bracelet.
Carboxylic Acid: This is an organic compound containing both a carbonyl (>C=O) and a hydroxyl (–OH) group on the same carbon atom.