Term: floc
https://doi.org/10.1351/goldbook.F02428

Definition:
When a sol is colloidally unstable the formation of aggregates is called coagulation or flocculation. Some authors distinguish between coagulation and flocculation, the latter implying the formation of a loose or open network which may or may not separate macroscopically. The loose structure formed in this way is called a floc.

Related Terms:
1) sol (http://doi.org/10.1351/goldbook.S05727).
2) coagulation (<em>in colloid chemistry</em>) (http://doi.org/10.1351/goldbook.C01117).
3) flocculation (<em>in colloid chemistry</em>) (http://doi.org/10.1351/goldbook.A00182-2).
4) unstable (http://doi.org/10.1351/goldbook.U06569).
5) network (<em>in colloid chemistry</em>) (http://doi.org/10.1351/goldbook.NT07562).
6) coagulation (<em>in colloid chemistry</em>) (http://doi.org/10.1351/goldbook.A00182-1).

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)

Citation: 'floc' 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.F02428

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.