Lone Pair Stereoactivity and Material Properties

The stereoactivity of the lone pair, or absence of, can have serious implications on the chemical and physical properties of the materials. Some of these were described above and used to help determine their crystal structure. 

Divalent tin has a lone pair of electrons, therefore not used for bonding, and it can be stereoactive (hybridized, axial) or nonstereoactive (unhybridized, spherical). The stereoactivity of the lone pair can be easily evaluated by Sn Mossbauer spectroscopy and this information can be used to help crystallographic methods for determining the structure of tin (ll)-containing materials in particularly difficult cases. This method has been applied to four different types of problems  

None of the above phases, particularly the disordered ones could have been properly understood without the extensive use of Sn Mossbauer spectroscopy. In addition, it v/as shown that the correlation of the Mossbauer spectrum with crystallographic data could avoid trying folse solutions unnecessarily and greatly speed up solving the crystal structure, as shown by the a-Snp2 example. 

Pannetier,). Lucas,). Solid State Chem. 1980, 33, l-l I. 

Donaldson, R. Oteng, B.J. Senior,). Chem. Soc, Chem. Common. I96S, 618-619. 

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