https://doi.org/10.1351/goldbook.09631
Net attractive interaction between an electrophilic region associated with a chalcogen atom in a molecular entity and a nucleophilic region in another, or the same, molecular entity.
Notes:
- A typical chalcogen bond is denoted by the three dots in \(\ce{R–Ch···A}\), where \(\ce{Ch}\) is the \(\ce{ChB}\) donor, being any chalcogen atom (possibly hypervalent) having an electrophilic (electron-poor) region, \(\rm{R}\) is the remainder of the molecular entity \(\ce{R–Ch}\) containing the \(\ce{ChB}\) donor, and \(\rm{A}\) is the \(\ce{ChB}\) acceptor and is typically a molecular entity possessing at least one nucleophilic (electron-rich) region.
- Chalcogen atoms can concurrently form one or more than one chalcogen bond.
- Chalcogen atoms of a molecular entity give rise to a variety of interactions with different electronic and geometric features. The term chalcogen bond must not be used for interactions where the chalcogen (frequently oxygen) functions as a nucleophile. The attractive intermolecular interaction between the oxygen atoms of an alcohol or a carboxylic acid and the acidic proton of another alcohol or carboxylic acid molecule is not a chalcogen bond, it is a hydrogen bond; the attractive intermolecular interaction between 1,4-dithiane and iodine atoms of diiodine or triiodomethane is not a chalcogen bond, it is a halogen bond; the attractive intermolecular interaction between bismuth and selenium atoms of tris(selenophen-2-yl)-bismuthane is not a chalcogen bond, it is a pnictogen bond (PnB); and the attractive intramolecular interactions between tin and sulphur atoms in crystalline 2,10-dichloro-2,10-dimethyl-2,10-distanna-6-thiaundecane is not a chalcogen bond, it is a tetrel bond (\(\ce{TtB}\)).