association

https://doi.org/10.1351/goldbook.A00472
The assembling of separate @M03986@ into any aggregate, especially of oppositely charged free ions into @I03231@ or larger and not necessarily well-defined clusters of ions held together by electrostatic attraction. The term signifies the reverse of @D01801@, but is not commonly used for the formation of definite @A00138@ by @C01153@ or @C01329@.
Source:
PAC, 1994, 66, 1077. (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1086 [Terms] [Paper]