chain reaction

https://doi.org/10.1351/goldbook.C00960
A reaction in which one or more reactive reaction intermediates (frequently radicals) are continuously regenerated, usually through a repetitive cycle of elementary steps (the 'propagation step'). For example, in the chlorination of methane by a radical mechanism, Cl· is continuously regenerated in the chain propagation steps:
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C00960-2.png
In chain polymerization reactions, reactive intermediates of the same types, generated in successive steps or cycles of steps, differ in relative molecular mass, as in:
C00960-3.png
See also: chain branching, chain transfer, degenerate chain branching, initiation, termination
Sources:
PAC, 1993, 65, 2291. 'Nomenclature of kinetic methods of analysis (IUPAC Recommendations 1993)' on page 2293 (https://doi.org/10.1351/pac199365102291)
PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1094 (https://doi.org/10.1351/pac199466051077)
PAC, 1996, 68, 149. 'A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC Recommendations 1996)' on page 157 (https://doi.org/10.1351/pac199668010149)