New Quaternary Tellurite and Selenite: Synthesis, Structure, and Characterization of Centrosymmetric InVTe2O8 and Noncentrosymmetric InVSe2O8

Abstract

Two new quaternary mixed metal oxide materials InVTe2O8 and InVSe2O8 have been synthesized, as crystals and pure bulk powders by standard solid-state reactions using In2O3, V2O5, and TeO2 (or SeO2) as reagents. The crystal structures of the reported materials were determined using single-crystal X-ray diffraction. InVTe2O8 crystallizes in the monoclinic centrosymmetric space group P2(1)/n (No. 14), with unit-cell parameters of a = 7.8967(16) angstrom, b = 5.1388(10) angstrom, c = 16.711(3) angstrom, beta = 94.22(3)degrees, and Z = 4, and InVSe2O8 crystallizes in the noncentrosymmetric space group Pm (No. 6) with unit-cell parameters of a = 4.6348(9) angstrom, b = 6.9111(14) angstrom, c = 10.507(2) angstrom, beta = 97.77(3)degrees, and Z = 2. While the centrosymmetric InVTe2O8 shows a two-dimensional (2D) layered structure composed of InO6 octahedra, VO4 tetrahedra, and TeO4 polyhedra, the noncentrosymmetric InVSe2O8 exhibits a three-dimensional (3D) framework structure with distorted InO6 octahedra, VO5 square pyramids, and SeO3 polyhedra. Powder second-harmonic generation (SHG) measurements on InVSe2O8, using 1064-nm radiation, indicate that the material has a SHG efficiency similar to 30 times that of alpha-SiO2. Additional SHG measurements reveal that the material is not phase-matchable (Type 1). Infrared, ultraviolet visible light (UV-vis) diffuse reflectance, and thermogravimetric analyses for the two compounds are also presented, as are dipole moment calculations.