(1) As in Sections A and B, the following rules are written, solely for uniformity, in accord with the conventions of Chemical Abstracts for spelling, position of numerals, punctuation, italicising, abbreviations, elision of vowels, and certain terminations, and are not to be considered as recommendations by the Commission in these respects. However, it is hoped that variations therefrom may be reduced so far as practicable.

(2) Except where specifically stated to the contrary, symbols R, etc., are used to denote univalent radicals attached by means of carbon and derived from aliphatic, carbocyclic, or heterocyclic compounds, which may be saturated or unsaturated, and unsubstituted or substituted, but they are not used for -CN, -CNO, -CNS, or -CNSe groups or for groups attached directly through >C=X where X is O, S, Se, Te, NH, or substituted NH. Up to three such groups may be designated R, R', and R'', or , , and ; for more than three different groups the sequence , , , . . . is recommended (where numerals are used, the simple R is not included). , , and should be used only to denote two, three, or four, respectively, of the same group denoted by simple R. For simplicity, in the rules in this Report only , . . . etc. are used.

Individual Rules of the I.U.P.A.C. 1957 Rules are cited in the present text as Rule A-2, Rule B-3.4, etc.


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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