Term: additivity principle
https://doi.org/10.1351/goldbook.A00137

Definition:
The hypothesis that each of several structural features of a molecular entity makes a separate and additive contribution to a property of the substance concerned. More specifically, it is the hypothesis that each of the several substituent groups in a parent molecule makes a separate and additive contribution to the standard Gibbs energy change (or Gibbs energy of activation) corresponding to a particular equilibrium (or rate of reaction).

Related Terms:
1) transferability (http://doi.org/10.1351/goldbook.T06441).
2) molecular entity (http://doi.org/10.1351/goldbook.M03986).
3) substituent (http://doi.org/10.1351/goldbook.S06076).
4) gibbs energy of activation (http://doi.org/10.1351/goldbook.G02631).
5) rate of reaction (http://doi.org/10.1351/goldbook.R05156).
6) additive (http://doi.org/10.1351/goldbook.A00134).

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: 'additivity principle' 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.A00137

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