Term: hydration
https://doi.org/10.1351/goldbook.H02876

Definition:
addition of water or of the elements of water (i.e. H and OH) to a molecular entity. For example, hydration of ethene: H02876-1.png The term is also used in a more restricted sense for the process: H02876-2.png

Note: Compare the use of the term in inorganic/physical chemistry to describe the state of the ions of an electrolyte in aqueous solution.

Related Terms:
1) aquation (http://doi.org/10.1351/goldbook.A00426).
2) solvation (http://doi.org/10.1351/goldbook.S05747).
3) addition (http://doi.org/10.1351/goldbook.A00132).
4) molecular entity (http://doi.org/10.1351/goldbook.M03986).

Images:
1) Not defined (https://goldbook.iupac.org/img/inline/H02876-1.png) 
2) Not defined (https://goldbook.iupac.org/img/inline/H02876-2.png) 

Source: PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1122 (https://doi.org/10.1351/pac199466051077)

Citation: 'hydration' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. https://doi.org/10.1351/goldbook.H02876

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.

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