Title: Schulze–Hardy rule
Long Title: IUPAC Gold Book - Schulze–Hardy rule
DOI: 10.1351/goldbook.S05501
Status: current

Definition
The generalization that the critical coagulation concentration for a typical lyophobic sol is extremely sensitive to the valence of the counter-ions (high valence gives a low critical coagulation concentration).

Related Terms
- coagulation: https://goldbook.iupac.org//terms/view/C01117
- coagulation: https://goldbook.iupac.org//terms/view/A00182
- counter-ions: https://goldbook.iupac.org//terms/view/C01371
- lyophobic sol: https://goldbook.iupac.org//terms/view/L03655
- valence: https://goldbook.iupac.org//terms/view/V06588

Source
- PAC, 1972, 31, 577. 'Manual of Symbols and Terminology for Physicochemical Quantities and Units, Appendix II: Definitions, Terminology and Symbols in Colloid and Surface Chemistry' on page 610 (https://doi.org/10.1351/pac197231040577)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/S05501/html
- json: https://goldbook.iupac.org/terms/view/S05501/json
- xml: https://goldbook.iupac.org/terms/view/S05501/xml

Citation: Citation: 'Schulze–Hardy rule' 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.S05501
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Accessed: 2026-05-18T04:01:25+00:00