{"term":{"id":"15152","title":"angle of repose","longtitle":"IUPAC Gold Book - angle of repose","doi":"10.1351\/goldbook.15152","code":"15152","status":"current","definitions":[{"id":1,"text":"Characteristic angle of slope formed with the horizontal by the side of a static conical mound of powder.","notes":{"1":"Angle of repose is determined by a balance of gravitational force and the frictional forces caused by interparticulate interactions.","2":"A measure of cohesiveness in powders. The smaller the angle of repose the greater the ability of the powder to flow. A particle will begin to slide on a slope when the angle of inclination is sufficiently large to overcome the frictional forces, and conversely the particle will not move when the angle is below that required to overcome cohesion and adhesion.","3":"The angle of repose depends on the method of measurement."},"links":[{"term":"powder","url":"https:\/\/goldbook.iupac.org\/terms\/view\/15227"}],"sources":["PAC, 2009, 81, 971. 'Glossary of terms related to pharmaceutics (IUPAC Recommendations 2009)' on page 976 (https:\/\/doi.org\/10.1351\/PAC-REC-04-10-14)"]}],"altoutputs":{"html":"https:\/\/goldbook.iupac.org\/terms\/view\/15152\/html","xml":"https:\/\/goldbook.iupac.org\/terms\/view\/15152\/xml","plain":"https:\/\/goldbook.iupac.org\/terms\/view\/15152\/plain"},"citation":"Citation: 'angle of repose' 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.15152","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":"2026-05-13T19:33:34+00:00"}}