Illustrated Glossary of Organic Chemistry

Radical halogenation (free radical halogenation): A substitution reaction in which a hydrogen atom is replaced with a halogen atom, via a free radical reaction mechanism.

Industrial scale synthesis of chloromethane (CH₃Cl) is achieved by gas-phase radical halogenation of methane with chlorine. Further halogenation can give dichloromethane (methylene chloride), trichloromethane (chloroform), and carbon tetrachloride.