An addition reaction, in chemistry, is in its simplest terms an organic reaction where two or more molecules combine to form a larger one.

There are two main types of polar addition reactions:

• Electrophilic addition
• Nucleophilic addition

Other non-polar addition reactions exists as well:

• Free radical addition

Addition reactions are limited to chemical compounds that have multiply-bonded atoms:

• Molecules with carbon-carbon double bonds or triple bonds
• Molecules with carbon - hetero double bonds like C=O or C=N

An addition reaction is the opposite of an elimination reaction. For instance the hydration reaction of an alkene and the dehydration of an alcohol are addition-elimination pairs.

See also

• Addition reactions are applied in addition polymerization.

Organic reactions

تفاعل إضافة | Reazione di addizione | 付加反応 | Additioreaktio | 加成反应