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Schlagwörter:
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Zusammenfassung:
Clathrates represent a family of inorganic materials called cage
compounds. The key feature of their crystal structures is a
three-dimensional (host) framework bearing large cavities (cages) with
20-28 vertices. These polyhedral cages bear-as a rule-guest species.
Depending on the formal charge of the framework, clathrates are grouped
in anionic, cationic and neutral. While the bonding in the framework is
of (polar) covalent nature, the guest-host interaction can be ionic,
covalent or even van-der Waals, depending on the chemical composition of
the clathrates. The chemical composition and structural features of the
cationic clathrates can be described by the enhanced Zintl concept,
whereas the composition of the anionic clathrates deviates often from
the Zintl counts, indicating additional atomic interactions in
comparison with the ionic-covalent Zintl model. These interactions can
be visualized and studied by applying modern quantum chemical approaches
such as electron localizability.
