Term: guest
https://doi.org/10.1351/goldbook.G02711

Definition:
An organic or inorganic ion or molecule that occupies a cavity, cleft or pocket within the molecular structure of a host molecular entity and forms a complex with it or that is trapped in a cavity within the crystal structure of a host.

Related Terms:
1) crown (http://doi.org/10.1351/goldbook.C01421).
2) cryptand (http://doi.org/10.1351/goldbook.C01426).
3) inclusion compound (http://doi.org/10.1351/goldbook.I02998).
4) host (<em>in biotechnology</em>) (http://doi.org/10.1351/goldbook.H02859).
5) complex (<em>in biotechnology</em>) (http://doi.org/10.1351/goldbook.C01203).

Source: PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1118 (https://doi.org/10.1351/pac199466051077)

Citation: 'guest' 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.G02711

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.

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.