The bonding number

of a
skeletal atom is the sum of the total number of bonding equivalents (
valence bonds) of that
skeletal atom to adjacent skeletal atoms in a
parent hydride, if any, and the number of attached hydrogen atoms, if any. Examples:
SH2:
for S,

;
SH6:
for S,

.
Source:
See also:
PAC, 1984, 56, 769
(Treatment of variable valence in organic nomenclature (lambda convention) (Recommendations
1983))
on page 774
Cite as:
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by
A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997).
XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic,
J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8.
https://doi.org/10.1351/goldbook.