01977 IUPAC Gold Book - electron affinity 10.1351/goldbook.E01977 E01977 current 1 Energy required to detach an electron from the singly charged negative ion (energy for the process ). The equivalent more common definition is the energy released (\(E_{\rm{initial}} - E_{\rm{final}}\)) when an additional electron is attached to a neutral atom or molecule. Green Book, 2nd ed., p. 20 (https://goldbook.iupac.org/files/pdf/green_book_2ed.pdf) PAC, 1991, 63, 1541. 'Recommendations for nomenclature and symbolism for mass spectroscopy (including an appendix of terms used in vacuum technology). (Recommendations 1991)' on page 1546 (https://doi.org/10.1351/pac199163101541) PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1109 (https://doi.org/10.1351/pac199466051077) https://goldbook.iupac.org/terms/view/E01977/html https://goldbook.iupac.org/terms/view/E01977/json https://goldbook.iupac.org/terms/view/E01977/plain Citation: 'electron affinity' 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.E01977 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. If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org . 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. 2026-06-10T04:40:54+00:00