Term: steric factor https://doi.org/10.1351/goldbook.S05998 Definition: A factor introduced into simple versions of the collision theory of reactions to take care of the fact that the reaction probability depends on the certain mutual orientations of the reactant molecules. Related Terms: 1) collision frequency (http://doi.org/10.1351/goldbook.C01166). 2) collision theory (http://doi.org/10.1351/goldbook.C01170). 3) reaction probability (http://doi.org/10.1351/goldbook.R05176). Source: PAC, 1996, 68, 149. 'A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC Recommendations 1996)' on page 187 (https://doi.org/10.1351/pac199668010149) Citation: 'steric factor' 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.S05998 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.