https://doi.org/10.1351/goldbook.C01203
A @M03986@ formed by loose @A00472@ involving two or more component molecular entities (ionic or uncharged), or the corresponding @CT01038@. The bonding between the components is normally weaker than in a covalent @B00697@. The term has also been used with a variety of shades of meaning in different contexts: it is therefore best avoided when a more explicit alternative is applicable. In inorganic chemistry the term '@C01330@' is recommended instead of 'complex'.
Source:
PAC, 1994, 66, 1077. (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1098 [Terms] [Paper]