Signifies, with its superscript, the
bonding number, i.e. the sum of the number of skeletal bonds to an atom and the number of hydrogen atoms associated with it in a
parent hydride, real or hypothetical. Its usage in names of compounds is generally restricted to non-standard
valence states.
Source:
PAC, 1984, 56, 769
(Treatment of variable valence in organic nomenclature (lambda convention) (Recommendations 1983))
on page 774
See also:
Blue Book, p. 465Red Book, p. 245
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.
doi:10.1351/goldbook.
