{"term":{"id":"04063","title":"multiply labelled","longtitle":"IUPAC Gold Book - multiply labelled","doi":"10.1351\/goldbook.M04063","code":"M04063","status":"current","definitions":[{"id":1,"text":"A selectively labelled compound may be multiply labelled when in the unmodified compound there is more than one atom of the same element at the position where the isotopic modification occurs, e.g. $\\ce{H}$ in $\\ce{CH4}$, or there are several atoms of the same element at different positions where the isotopic modification occurs, e.g. $\\ce{C}$ in $\\ce{C4H8O}$.","links":[{"term":"selectively labelled","url":"https:\/\/goldbook.iupac.org\/terms\/view\/S05556"}],"sources":["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)"]}],"altoutputs":{"html":"https:\/\/goldbook.iupac.org\/terms\/view\/M04063\/html","xml":"https:\/\/goldbook.iupac.org\/terms\/view\/M04063\/xml","plain":"https:\/\/goldbook.iupac.org\/terms\/view\/M04063\/plain"},"citation":"Citation: 'multiply 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.M04063","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.","collection":"If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org .","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.","accessed":"2026-06-29T13:18:05+00:00"}}