Note: In some languages the word "acid" is included before "anhydride".
Examples to Rule C-491.1
491.2 - Anhydrides of substituted monocarboxylic acids, if symmetrically substituted, are named by prefixing "bis-'' to the name of the acid and replacing the word "acid" by "anhydride''. The "bis'' may, however, be omitted.
491.3 - Mixed anhydrides (anhydrides of different monobasic acids) are named by giving in alphabetical order the first (i.e., the specific) part of the names of the two acids, followed by "anhydride''.
Examples to Rule C-491.2
491.4 - Cyclic anhydrides of polycarboxylic acids, although possessing a heterocyclic structure, are preferably named as acid anhydrides, as in Rule C-491.1 but with any necessary locants.
Examples to Rule C-491.3
See Recommendations'93 R-5.7.7
Examples to Rule C-491.4
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