{"term":{"id":"09157","title":"coulometer","longtitle":"IUPAC Gold Book - coulometer","doi":"10.1351\/goldbook.09157","code":"09157","status":"current","definitions":[{"id":1,"text":"Measuring instrument to obtain the electrical charge passed in an experiment, or to produce a known amount of substance in a titration.","notes":{"1":"The silver coulometer is a primary reference measurement procedure for charge and current. By weighing the mass of silver deposited in a known time at constant current, the charge and current are calculated from Faraday’s laws of electrolysis.","2":"Modern instruments for measuring trace water by Karl Fischer titration use the passage of a measured charge to produce iodine from iodide solution. They are known as Karl Fischer coulometers."},"links":[{"term":"Faraday’s laws of electrolysis","url":"https:\/\/goldbook.iupac.org\/\/terms\/view\/09075"},{"term":"coulometric titration","url":"https:\/\/goldbook.iupac.org\/\/terms\/view\/09158"}],"sources":["PAC, 2020, 92, 641. 'Terminology of Electrochemical Methods of Analysis (IUPAC Recommendations 2019)' on page 682 (https:\/\/doi.org\/10.1515\/pac-2018-0109)"]}],"altoutputs":{"html":"https:\/\/goldbook.iupac.org\/terms\/view\/09157\/html","xml":"https:\/\/goldbook.iupac.org\/terms\/view\/09157\/xml","plain":"https:\/\/goldbook.iupac.org\/terms\/view\/09157\/plain"},"citation":"Citation: 'coulometer' 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.09157","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":"2026-05-01T09:54:59+00:00"}}