Minerals and synthetic Pb(II) compounds with oxocentered tetrahedra: review and classification

Abstract

The crystal structures of minerals and inorganic compounds with OPb 4 oxocentered tetrahedra are reviewed. It is shown that the OPb 4 tetrahedral units may link by sharing common Pb atoms to form structural units of various shape and dimensionality. These units determine basic topology of the structures and influence their stability and properties. The high strength of the OPb 4 te trahedral units involves interplay between high basicity of additional O 2– anions and stereochemical activity of the 6 s 2 lone electron pairs on Pb 2+ cations. The structural chemistry of polycations based upon OPb 4 tetrahedra, in general, follows major trends previously observed for cation-centered tetrahedral units (silicates, phosphates, metal sulphides with MS 4 tetrahedra, etc.). One may conclude that the basic structural correlations depend upon size and charge parameters of the ions only, irrespective of their positive or negative sign.