Piezoelectricity, ferroelectricity, and second order non-linear optical behavior are all possible with noncentrosymmetric materials. The distortion results in a pool of polarized electrons. Anions assembled in a crystal with their distortions aligned would result in a sea of polarized electrons creating a substantial NLO response. Two goals must be met in order to produce an acentric structure from polar anions. These interesting mixed transition metal oxide fluorides are easily prepared by hydrothermal reactions.
Hydrothermal synthesis provides a low temperature pathway to interesting solid state compounds.
Single crystals of new mixed metal compounds are recovered after slow cooling of the solutions. To address the second condition for the formation of an acentric structure, the synthesis of a three-dimensional structure of linked anions and cations is being studied. This could involve using different ligands with additional bonding sites to coordinate to the copper cation which would connect the above linear chains together, using a tetrahedral cation rather than an octahedral cation. 4 Cr 2 O 7 compound. This crystal structure contains polar chains of two vertex sharing chromium-centered tetrahedra that shares an oxygen on each end with a copper octahedron, which is ligated around the waist by pyridine.