Functional groups are groups of atoms with specific chemical properties that occur within organic molecules and are sometimes denoted as “R”. Functional groups can “functionalize” a compound by enabling it to adopt different physical and chemical properties.

Types of Advanced Functional Groups

The table below summarizes some of the major functional groups in organic chemistry.

Class of Organic Compounds	Skeletal Structures of Compounds with Functional Groups in Red	Names of Compounds
Aromatic hydrocarbon		Benzene
Phenol		Phenol (Hydroxybenzene)
Aldehyde		Ethanal (Acetaldehyde)
Ketone		Acetone
Acid or acyl chloride		Acetyl chloride
Carboxylic acid		Ethanoic acid (Acetic acid)
Ester		Ethyl acetate
Amine		Ethylamine
Amide		Acetamide
Nitrile		Acetonitrile
Phosphate		Methyl dihydrogen phosphate

This text is adapted from Openstax, Chemistry 2e, Section20.2: Alcohols and EthersandSection 20.3: Aldehydes, Ketones, Carboxylic Acids, and Esters.