Term: activated complex
https://doi.org/10.1351/goldbook.A00092

Definition:
An activated complex, often characterized by the superscript ‡, is defined as that assembly of atoms which corresponds to an arbitrary infinitesimally small region at or near the col (saddle point) of a potential energy surface.

Related Terms:
1) transition state (http://doi.org/10.1351/goldbook.T06468).
2) saddle point (http://doi.org/10.1351/goldbook.C01145).

Source: PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1081 (https://doi.org/10.1351/pac199466051077)

Citation: 'activated complex' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.A00092

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