The number of reactant
molecular entities that are involved in the '
microscopic chemical event' constituting an
elementary reaction. (For reactions in solution this number is always taken to exclude molecular entities
that form part of the
medium and which are involved solely by virtue of their
solvation of solutes.) A reaction with a molecularity of one is called '
unimolecular', one with a molecularity of two '
bimolecular' and of three '
termolecular'.
Source:
PAC, 1994, 66, 1077
(Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994))
on page 1143
PAC, 1996, 68, 149
(A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC
Recommendations 1996))
on page 175
PAC, 1993, 65, 2291
(Nomenclature of kinetic methods of analysis (IUPAC Recommendations 1993))
on page 2296