{"term":{"id":"15350","title":"reciprocal salt system","longtitle":"IUPAC Gold Book - reciprocal salt system","doi":"10.1351\/goldbook.15350","code":"15350","status":"current","definitions":[{"id":1,"text":"System containing \\(n\\) ionic species with or without a single solvent. Because of electrical neutrality, the system has \\(n\\) components in an aqueous system with a single solvent and \\(n - 1\\) components in a molten salt system.","notes":{"1":"There is a special notation for reciprocal salt systems that involves use of double vertical bars. All ionic species are specified. For example, \\[\\ce{K^{+},Na^{+} \\Vert\\ Cl^{-},NO3^{-} + H2O}\\] denotes a four-component (quaternary) aqueous reciprocal salt system in which each cation can combine with each anion to produce anhydrous, hydrated, binary, or ternary solid components; i.e., the solution may become saturated with respect to any one of \\(\\ce{KCl}\\), \\(\\ce{NaCl}\\), \\(\\ce{KNO3}\\), \\(\\ce{NaNO3}\\), their hydrates, or anhydrous or hydrated binary compounds of the simple salts.","2":"Ternary aqueous systems containing a common ion can be considered as a limiting case of this class of system, where there is only one cation or one anion. For example, \\[\\ce{Na^{+},Zn^{2+} \\Vert\\ SO4^{2-} + H2O}\\]"},"sources":["PAC, 2008, 80, 233. 'Glossary of terms related to solubility (IUPAC Recommendations 2008)' on page 260 (https:\/\/doi.org\/10.1351\/pac200880020233)"]}],"altoutputs":{"html":"https:\/\/goldbook.iupac.org\/terms\/view\/15350\/html","xml":"https:\/\/goldbook.iupac.org\/terms\/view\/15350\/xml","plain":"https:\/\/goldbook.iupac.org\/terms\/view\/15350\/plain"},"citation":"Citation: 'reciprocal salt system' 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.15350","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":"2026-07-25T22:30:08+00:00"}}