Nomenclature Systems

Rule D-1.6 Replacement Nomenclature

1.60 - The system of naming organic compounds in which carbon atoms have been replaced by heteroatoms has been described in Section B for cyclic compounds: Rule B-4, "a" Nomenclature, and in Section C for acyclic compounds: Subsection C-0.6, Replacement nomenclature.

In Section D, this system is broadened by extending Table B-I of Rule B-1 to include most of the elements. The corresponding "a" terms are given in Table D-I. This seniority order of elements is based upon the element sequence given in Table IV of "Nomenclature of Inorganic Chemistry, 1970", and supersedes Rule B-1.4.

1.61 - The affixes listed in Table D-I in decreasing order of priority are used according to the principles stated in Subsection C-0.6 for acyclic structures and in Rule B-4 for heterocyclic systems. These prefixes are used alone when the heteroatoms considered in the structure have the normal bonding number. The accepted normal bonding numbers are the following:

Elements Normal bonding number
F, Cl, Br, I, At 1
O, S, Se, Te, Po 2
N, P, As, Sb, Bi 3
C, Si, Ge, Sn, Pb 4
B, Al, Ga, In, Tl 3
Be, Mg, Zn, Cd, Hg 2

Examples to Rule D-1.61


Methyl 3-phospha-5-silahexanoate

1.62 - When the bonding number of a neutral heteroatom is other than that given in Rule D-1.61 or if the heteroatom is not listed under that rule, the bonding number is expressed by an Arabic number cited as a superscript to the Greek letter which follows the locant for the heteroatom. If no locant for the heteroatom normally appears in the name for the parent compound, the l symbol and an appropriate locant are prefixed to that part of the name which designates the heteroatom.

Note: - In some cases, bonding numbers higher than those listed in Rule D-1.61 may be indicated by hydro prefixes according to Rule D-1.53.

Examples to Rule D-1.62

1.63 - Ionic heteroatoms are expressed, whenever possible, by the usual terms such as "-onium", "-ium", "-ide", "-onia", "-ata", with their usual meaning (see Subsections C-0.8 and D-7.63) associated with normal bonding numbers.

Examples to Rule D-1.63

Tetramethylphosphonium bromide

Pyridinium perchlorate

Sodium 4a-borataanthracene

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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