Title: intramolecular isotope effect
Long Title: IUPAC Gold Book - intramolecular isotope effect
DOI: 10.1351/goldbook.I03132
Status: current

Definition
A kinetic isotopic effect observed when a single substrate, in which the isotopic atoms occupy equivalent reactive positions, reacts to produce a non-statistical distribution of isotopomeric products. In such a case the isotope effect will favour the pathway with lower force constants for displacement of the isotopic nuclei in the transition state.

Related Terms
- force constants: https://goldbook.iupac.org//terms/view/F02481
- isotope effect: https://goldbook.iupac.org//terms/view/I03327
- isotopomeric: https://goldbook.iupac.org//terms/view/I03352
- kinetic isotopic effect: https://goldbook.iupac.org//terms/view/K03405
- transition state: https://goldbook.iupac.org//terms/view/T06468

Source
- PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1130 (https://doi.org/10.1351/pac199466051077)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/I03132/html
- json: https://goldbook.iupac.org/terms/view/I03132/json
- xml: https://goldbook.iupac.org/terms/view/I03132/xml

Citation: Citation: 'intramolecular isotope effect' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.I03132
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Accessed: 2026-06-10T10:08:44+00:00