chain-propagating steps

In chemistry, a chain reaction is a self-sustaining sequence of events where the product of one step initiates further steps of the same kind. These reactions typically involve three stages: initiation, propagation, and termination.12

• Initiation: A reactive intermediate (atom, ion, or molecular fragment) is formed, often by heat, light, or a catalyst.1
• Propagation: The intermediate reacts with reactants, creating products and a new intermediate. This new intermediate then reacts similarly, continuing the cycle. This is the core of the chain-propagating steps.12
• Termination: The reaction ends, either naturally when reactants are consumed or by introducing inhibitors.1

Branching chain reactions, where the number of intermediates increases, can lead to very rapid acceleration and explosions. Chain reactions are crucial in processes like polymerization and nuclear fission.12