Term: electronic state https://doi.org/10.1351/goldbook.ET07026 Definition: An arrangement allowed by the laws of quantum mechanics of electrons within an atom, molecule (or system of molecules). Source: PAC, 1999, 71, 1919. 'Glossary of terms used in theoretical organic chemistry' on page 1937 (https://doi.org/10.1351/pac199971101919) Citation: 'electronic state' 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.ET07026 License: The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms. Disclaimer: The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using.