termination

In chemistry, a termination step is the final process in a chain reaction where the reactive intermediates are consumed, stopping the chain's growth. This can occur through the combination of two growing chains or by a disproportionation reaction, where a hydrogen atom is transferred between chains. For example, in the polymerization of Teflon, peroxides initiate the reaction by forming free radicals, which then propagate by adding tetrafluoroethylene molecules. The chain reaction eventually ends when these radicals combine. Termination signifies the cessation of a process or activity.123