Azo compounds (R-N=N-R') can be the precursor of two carbon-centered radicals (R• and R'•) and nitrogen gas upon heating and/or by irradiation. For example, AIBN and ABCN yield isobutyronitrile and cyclohexanecarbonitrile radicals, respectively.
Inorganic peroxides function analogously to organic peroxides. Many polymers are often produced from the alkenes upon initiation with peroxydisulfate salts. In solution, peroxydisulfate dissociates to give sulfate radicals:
[O3SO-OSO3]2− ⇌ 2 [SO4]−
The sulfate radical adds to an alkene forming radical sulfate esters, e.g. .CHPhCH2OSO3−, that add further alkenes via formation of C-C bonds. Many styrene and fluoroalkene polymers are produced in this way.
In atom transfer radical polymerization (ATRP) carbon-halides reversibly generate organic radicals in the presence of transition metalcatalyst.
General ATRP Reaction. A. Initiation. B. Equilibrium with dormant species. C.Propagation
Some radical initiators such as azo compounds and peroxides can detonate at elevated temperatures so they must be stored cold.
^March, Jerry (1985), Advanced Organic Chemistry: Reactions, Mechanisms, and Structure (3rd ed.), New York: Wiley, ISBN 0-471-85472-7
^Smith, Michael B.; March, Jerry (2007), Advanced Organic Chemistry: Reactions, Mechanisms, and Structure (6th ed.), New York: Wiley-Interscience, ISBN 978-0-471-72091-1
^Harald Jakob, Stefan Leininger, Thomas Lehmann, Sylvia Jacobi, Sven Gutewort. "Peroxo Compounds, Inorganic". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a19_177.pub2.CS1 maint: multiple names: authors list (link)