ACD/Name

Introduction

R-0.2.4 Other terms used in these recommendations

R-0.2.4.1 Seniority, senior: terms used in reference to priority in a prescribed hierarchical order, a senior feature being preferred.

R-0.2.4.2 Lowest set of locants: the set of locants, which when compared term by term with other locant sets, each in order of increasing magnitude, has the lowest term at the first point of difference; for example, the locant set 2,3,6,8 is lower than 3,4,6,8 or 2,4,5,7.

Primed locants are placed immediately after the corresponding unprimed locants in a set arranged in ascending order; locants consisting of a numeral and a lower-case letter are placed immediately after the corresponding numeric locant.

Examples to R-0.2.4.2

2 is lower than 2

3 is lower than 3a

8a is lower than 8b

4' is lower than 4a

4'a is lower than 4a'

Italic capital and lower-case letter locants are lower than Greek letter locants which, in turn, are lower than numerals.

Example to R-0.2.4.2

R-0.2.4.3 Bonding number: see R-1.1.


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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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