When alone, the numerical term for the number 1 is "mono-" and that for 2 is "di-". In association with other numerical terms, the number 1 is represented by "hen-" (except in the case of "undeca-")
and the number 2 by "do-" (except in the case of "dicta-" and "dilia-"). The numerical term for the number 11 is "undeca-". Compare monochloro with henicosane for the number 21 and
dichloro with docosane for the number 22.
This HTML reproduction is as close as possible to the published version [see IUPAC, Commission on Nomenclature of Organic Chemistry. A Guide to IUPAC Nomenclature of Organic Compounds
(Recommendations 1993), 1993, Blackwell Scientific publications, Copyright 1993 IUPAC]. If you need to cite these rules please quote this reference as their source.
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