08617 IUPAC Gold Book - infrared radiation 10.1351/goldbook.08617 08617 current initialism: IR synonym: infrared 1 Electromagnetic radiation of wavelength between approximately \(\pu{780 nm}\) and \(\pu{1000 \upmu m}\) or of wavenumber between approximately \(\pu{13000 cm-1}\) and \(\pu{10 cm-1}\). The infrared range is sub-divided into three regions: near-infrared: \(\pu{780 nm}\) to \(\pu{2.5 \upmu m}\) (\(\pu{12800 cm-1}\) to \(\pu{400 cm-1}\)); mid-infrared: \(\pu{2.5 \upmu m}\) to \(\pu{25 \upmu m}\) (\(\pu{4000 cm-1}\) to \(\pu{400 cm-1}\)) and far infrared: \(\pu{25 \upmu m}\) to \(\pu{1000 \upmu m}\) (\(\pu{400 cm-1}\) to \(\pu{10 cm-1}\)). The wavelength regions given are commonly used in chemistry and relate to working ranges of infrared spectrometers. Note that in other disciplines (e.g., astronomy) the terms are defined for different ranges. If there is no ambiguity the term 'infrared' is used for the mid-infrared region. Electromagnetic radiation https://goldbook.iupac.org//terms/view/08242 Raman spectroscopy https://goldbook.iupac.org//terms/view/08669 infrared spectroscopy https://goldbook.iupac.org//terms/view/08618 near-infrared https://goldbook.iupac.org//terms/view/08642 wavelength https://goldbook.iupac.org//terms/view/08300 wavenumber https://goldbook.iupac.org//terms/view/08302 PAC, 2021, 93, 647. 'Glossary of methods and terms used in analytical spectroscopy (IUPAC Recommendations 2019)' on page 750 (https://doi.org/10.1515/pac-2019-0203) https://goldbook.iupac.org/terms/view/08617/html https://goldbook.iupac.org/terms/view/08617/json https://goldbook.iupac.org/terms/view/08617/plain Citation: 'infrared radiation' 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.08617 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. 2026-06-28T18:58:15+00:00