primary species

in a chain polymerization
https://doi.org/10.1351/goldbook.08965
Species that is formed from an initiator or monomer molecule and that is capable of initiating polymerization.
Notes:
  1. In radical polymerization a primary radical may be formed by the action of heat, irradiation or electron-transfer.
  2. In radical polymerization, recombination of primary radicals and their reactions with other radicals leads to reduced initiator efficiency.
  3. The term 'primary species' is also used to designate a species centred on a primary carbon atom, for example, an ethyl radical.
See also: secondary species
Source:
PAC, 2022, 94, 1093. (Terminology for chain polymerization (IUPAC Recommendations 2021)) on page 1124 [Terms] [Paper]
Citation: 'primary species' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.08965 RIS BibTex EndNote
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