In a similar way, prefixes can be derived from other cation names by changing an ending "-ium", formed according to Rule C-82.2, C-82.4, C-83.1, or C-83.2, to "-io", for example pyridinium to pyridinio-.

This HTML reproduction of Sections A, B and C of IUPAC "Blue Book" is as close as possible to the published version [see Nomenclature of Organic Chemistry, Sections A, B, C, D, E, F, and H, Pergamon Press, Oxford, 1979. Copyright 1979 IUPAC.] If you need to cite these rules please quote this reference as their source.

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