The formation of a covalent
bond, the two shared electrons of which have come from only one of the two parts of the
molecular entity linked by it, as in the reaction of a
Lewis acid and a
Lewis base to form a
Lewis adduct; alternatively, the bonding formed in this way. In the former sense, it is the reverse
of
unimolecular heterolysis. '
Coordinate covalence' and '
coordinate link' are synonymous (obsolescent) terms. The synonym '
dative bond' is obsolete. (The origin of the bonding electrons has by itself no bearing on the
character of the bond formed. Thus, the formation of methyl chloride from a methyl
cation and a chloride ion involves coordination; the resultant bond obviously differs in
no way from the
C–Cl
bond in methyl chloride formed by any other path, e.g. by
colligation of a methyl radical and a chlorine atom.) The term is also used to describe the number
of
ligands around a
central atom without necessarily implying two-electron bonds.
Source:
PAC, 1994, 66, 1077
(Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994))
on page 1100
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.
