Title: poison
Long Title: IUPAC Gold Book - poison
DOI: 10.1351/goldbook.P04706
Status: current

Definition
An inhibitory substance characterized by its propensity to attach very strongly, by a true chemical bond (e.g. covalent) to the surface atoms or ions constituting the catalytically active sites. Poisons act in minute quantities. Typical poisons are $\ce{S}$, $\ce{As}$, etc. In most cases, activity and/or selectivity cannot be recovered without a drastic change in operating conditions (most often a regeneration). recovery, if at all, takes place very slowly and/or only partially.

Related Terms
- chemical bond: https://goldbook.iupac.org//terms/view/CT07009
- recovery: https://goldbook.iupac.org//terms/view/R05206
- selectivity: https://goldbook.iupac.org//terms/view/S05563

Source
- PAC, 1991, 63, 1227. 'Manual on catalyst characterization (Recommendations 1991)' on page 1244 (https://doi.org/10.1351/pac199163091227)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/P04706/html
- json: https://goldbook.iupac.org/terms/view/P04706/json
- xml: https://goldbook.iupac.org/terms/view/P04706/xml

Citation: Citation: 'poison' 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.P04706
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Accessed: 2026-04-27T15:05:13+00:00