Lexikon

a complex in which one component (the host) forms a cavity or, in the case of a crystal, a crystal lattice containing spaces in the shape of long tunnels or channels in which molecular entities of a second chemical species (the guest) are located. There is no covalent bonding between guest and host, the attraction being generally due to van der Waals forces. If the spaces in the host lattice are enclosed on all sides so that the guest species is ‘trapped’ as in a cage, such compounds are known as clathrates or ‘cage’ compounds’. (Source: IUPAC Compendium of Chemical Terminology, 2nd Edition, 1997) In environmental risk reduction the inclusion complex formation is used for removal of contaminants, e.g. toxic metals from ground water by zeolites, and for enhancing the solubility and bioavailability of organic contaminants in soil by applying cyclodextrins (see: "sugar flushing" technology, cyclodextrin Technology).