Illustrated Glossary of Organic Chemistry

Heterolytic bond cleavage (heterolytic cleavage; heterolysis): Bond breaking in which the bonding electron pair is split unevenly between the products. Heterolytic cleavage often produces at least one ion.

Examples of Heterolytic Bond Cleavage

Heterolysis of a carbon-leaving group bond is the rate-limiting step in the SN1 and E1 mechanisms.

Heterolysis of this oxonium ion produces a carbocation and water.

This mechanism step shows heterolysis of a Lewis acid-base complex. In this case the heterolysis products do not include an ion.