03512 IUPAC Gold Book - Lewis basicity 10.1351/goldbook.L03512 L03512 current 1 The thermodynamic tendency of a substance to act as a Lewis base. Comparative measures of this property are provided by the equilibrium constants for Lewis adduct formation for a series of Lewis bases with a common reference Lewis acid. Lewis acid https://goldbook.iupac.org/terms/view/L03508 Lewis adduct https://goldbook.iupac.org/terms/view/L03510 Lewis base https://goldbook.iupac.org/terms/view/L03511 donor number https://goldbook.iupac.org/terms/view/D01833 nucleophilicity https://goldbook.iupac.org/terms/view/N04251 PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1135 (https://doi.org/10.1351/pac199466051077) https://goldbook.iupac.org/terms/view/L03512/html https://goldbook.iupac.org/terms/view/L03512/json https://goldbook.iupac.org/terms/view/L03512/plain Citation: 'Lewis basicity' 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.L03512 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. 2026-05-11T13:18:19+00:00