Interrelationship of Micro- and Macrostructure with Physical Properties of Noncentrosymmetric Germanates

A set of approximate to 100 noncentrosymmetric germanates has been observed in reference to nonlinear optical properties. It has been found that, on the plane of the oxide bond lengths, the noncentrosymmetric germanate crystals are positioned into three intersected ellipses of << acentricity >>. The nonlinear optical properties of -GeO2, space group P3(1)21, have been evaluated by powder method. The non-monotonic dependence of nonlinear optical susceptibility ((2)) on the shortest chemical bond length L(Ge-O) has been obtained for germanates. The suggested crystal chemistry analysis is useful for searching new noncentrosymmetric germanate crystals.