Title: degrees of triad isotacticity, syndiotacticity, and heterotacticity
Long Title: IUPAC Gold Book - degrees of triad isotacticity, syndiotacticity, and heterotacticity
DOI: 10.1351/goldbook.D01573
Status: current

Definition
The fractions of triads in a regular vinyl polymer that are of the mm, rr and mr = rm types, respectively. In cases where triad analysis is not attainable, the diad isotacticity and diad syndiotacticity may be defined as the fractions of diads in a regular vinyl polymer that are of the m and r types, respectively. (m = meso; r = racemic).

Related Terms
- meso: https://goldbook.iupac.org//terms/view/M03838
- polymer: https://goldbook.iupac.org//terms/view/P04735
- racemic: https://goldbook.iupac.org//terms/view/R05026
- triads: https://goldbook.iupac.org//terms/view/C01287

Source
- Purple Book, 1st ed., p. 45 (http://old.iupac.org/publications/books/author/metanomski.html)

Other Outputs
- html: https://goldbook.iupac.org/terms/view/D01573/html
- json: https://goldbook.iupac.org/terms/view/D01573/json
- xml: https://goldbook.iupac.org/terms/view/D01573/xml

Citation: Citation: 'degrees of triad isotacticity, syndiotacticity, and heterotacticity' 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.D01573
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Accessed: 2026-05-12T16:23:34+00:00