{"term":{"id":"02766","title":"helium dead-space","longtitle":"IUPAC Gold Book - helium dead-space","doi":"10.1351\/goldbook.H02766","code":"H02766","status":"current","definitions":[{"id":1,"text":"The position of the Gibbs surface is often defined experimentally as that surface which encloses the volume of space from which the solid excludes helium gas (the so-called helium dead-space), and is associated with the assumptions that the volume of the solid is unaffected by the adsorption of component i, and that helium is not adsorbed by the solid. This requires that the measurement of the helium dead-space be made at a sufficiently high temperature.","contexts":[],"links":[{"term":"Gibbs surface","url":"https:\/\/goldbook.iupac.org\/terms\/view\/G02635"},{"term":"adsorption","url":"https:\/\/goldbook.iupac.org\/terms\/view\/A00155"}],"sources":["PAC, 1972, 31, 577. 'Manual of Symbols and Terminology for Physicochemical Quantities and Units, Appendix II: Definitions, Terminology and Symbols in Colloid and Surface Chemistry' on page 595 (https:\/\/doi.org\/10.1351\/pac197231040577)"]}],"altoutputs":{"html":"https:\/\/goldbook.iupac.org\/terms\/view\/H02766\/html","xml":"https:\/\/goldbook.iupac.org\/terms\/view\/H02766\/xml","plain":"https:\/\/goldbook.iupac.org\/terms\/view\/H02766\/plain"},"citation":"Citation: 'helium dead-space' 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.H02766","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":"2026-08-10T00:34:10+00:00"}}