Radical substitution is a chemical reaction where a radical species replaces an atom or a group in a molecule. This process typically involves the breaking of a bond and the formation of a new bond, often occurring in alkanes and other hydrocarbons. The reaction is initiated by radicals, which are highly reactive species with unpaired electrons. In radical substitution, the most common example is the reaction of alkanes with halogens, such as chlorine or bromine. The reaction proceeds through three main steps: initiation, propagation, and termination. This method is significant in organic chemistry for synthesizing various compounds and understanding reaction mechanisms.