A rapidly reversible step preceding the rate-limiting step in a stepwise reaction. For example:
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See also: kinetic equivalence
Source:
PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1152 (https://doi.org/10.1351/pac199466051077)
See also:
PAC, 1996, 68, 149. 'A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC Recommendations 1996)' on page 177 (https://doi.org/10.1351/pac199668010149)