Iron polyhedron geometry

The coordination polyhedron geometry of tin-, antimony- and germanium-capped iron(II) dioximates was analyzed in the previous section. As mentioned above, the boron-capped clathrochelates have a distorted TP structure and positive QS values, whereas tin-, antimony- and germanium-capped clathrochelates have distorted TAP geometry, preferably for complexes with electronic configuration d , and a negative QS sign. 

The QS in the Fe Mdssbauer spectra is determined by the geometry of the iron(II) coordination polyhedron and has been utilized to gain information on the structure of the complexes from the spectral parameter vs structure correlation. Conversely, the data available on the structure of clathrochelates employed for working out a modern version of the partial quadrupole splitting (PQS) concept permits one to obtain absolute PQS values and to analyse the results for macrobicyclic complexes [264, 265]. 

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