Of a central atom
in a coordination entity
, the charge it would bear if all the ligands
were removed along with the electron pairs that were shared with the central atom
. It is represented by a Roman numeral.
See also: Red Book, p. 66
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