Archive:Introduction to Functional Groups

Introduction

Functional groups are groups of atoms within a molecule that affect its function. Some basic ones are listed below.

Hydroxyl Group

Hydroxyl Group

The hydroxyl group is formed by attaching a oxygen and a hydrogen atom to a molecule. Both the bond from the molecule to the oxygen and the bond from the oxygen to the hydrogen are single bonds; thus hydroxyl groups are usually denoted R-O-H. (where O is oxygen, H is hydrogen, and R is the molecule the hydroxyl group is attached to)

An organic compound that contains a hydroxyl group is called an alcohol.

Reactions of alcohols is covered in Section 4.2

Carbonyl Group

Carbonyl group

The Carbonyl group is formed by attaching a oxygen to a carbon by a double bond, then attaching that same carbon atom to a molecule. A carbonyl group is denoted X-C=O

Carboxyl Group

Carboxyl group

The carboxyl group is formed by starting with a carbonyl group , then attaching a hydroxyl group to the same carbon atom in the carbonyl group. Finally, the carboxyl group is added to a molecule. Because carbon has four bonding sites, and three of them are taken up by the hydrogen and oxygen, the bond from the carbon to the molecule is a single bond. A carboxyl group is denoted X-COH=O