Principles of Organic Nomenclature

R-1.1.2 Standard bonding numbers

The bonding number of a skeletal atom is standard when it has the value given in the following table:

Standard bonding number (n) Element
3 B
4 C Si Ge Sn Pb
3 N P As Sb Bi
2 O S Se Te Po
1 F Cl Br I At

R-1.1.3 Nonstandard bonding numbers
R-1.1.4 Contiguous formal double bonds

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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