09587 IUPAC Gold Book - heterotactic macromolecule 10.1351/goldbook.09587 09587 current 1 Regular macromolecule having a configurational repeating unit comprising four configurational base units, the first two stereogenic units of which are identical and enantiomorphic to the last two. A macromolecule consisting only of m and r diads in alternating sequence (i.e. mr and rm triads) is heterotactic. The configurational repeating unit consists of four configurational base units. The prefix ht- is recommended to indicate a heterotactic macromolecule. A heterotactic polypropylene can be depicted by a rotated Fischer Projection (top) and zigzag projection (bottom) as follows. The configurational repeating unit, a mrm tetrad, is shown within brackets. The configurational repeating unit can be equally well defined as a rmr tetrad. m https://goldbook.iupac.org//terms/view/09585 r https://goldbook.iupac.org//terms/view/09586 PAC, 2020, 92, 1769. 'Definitions and notations relating to tactic polymers (IUPAC Recommendations 2020)' on page 1776 (https://doi.org/10.1515/pac-2019-0409) https://goldbook.iupac.org/terms/view/09587/html https://goldbook.iupac.org/terms/view/09587/json https://goldbook.iupac.org/terms/view/09587/plain Citation: 'heterotactic macromolecule' 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.09587 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. If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org . 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. 2026-04-18T05:16:17+00:00