03943 IUPAC Gold Book - mixed labelled 10.1351/goldbook.M03943 M03943 current 1 A specifically labelled compound is referred to as mixed labelled when the isotopically substituted compound has more than one kind of modified atom e.g. $\ce{CH3–CH2–[^{18}O][^{2}H]}$. isotopically substituted https://goldbook.iupac.org/terms/view/I03338 specifically labelled https://goldbook.iupac.org/terms/view/S05793 Blue Book, p. 515 (https://www.acdlabs.com/iupac/nomenclature/) PAC, 1981, 53, 1887. 'Nomenclature of inorganic chemistry: II.1 - Isotopically modified compounds' on page 1893 (https://doi.org/10.1351/pac198153101887) https://goldbook.iupac.org/terms/view/M03943/html https://goldbook.iupac.org/terms/view/M03943/json https://goldbook.iupac.org/terms/view/M03943/plain Citation: 'mixed labelled' 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.M03943 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. 2026-06-29T13:33:12+00:00