Effect of the framework flexibility on the centricities in centrosymmetric In2Zn(SeO3)4 and noncentrosymmetric Ga2Zn(TeO3)4

The solid-state syntheses, crystal structures, and characterization of two stoichiometrically similar quaternary mixed metal selenite and tellurite, In(2)Zn(SeO(3))(4) and Ga(2)Zn(TeO(3))(4), respectively, are reported. While In(2)Zn(SeO(3))(4) crystallizes in the centrosymmetric monoclinic space group P2(1)/n (No. 14) with a = 8.4331(7) ?, b = 4.7819(4) ?, c = 14.6583(13) ?, and β = 101.684(6)°, Ga(2)Zn(TeO(3))(4) crystallizes in the non-centrosymmetric space group I-43d (No. 220) with a = b = c = 10.5794(8) ?. In(2)Zn(SeO(3))(4) exhibits a two-dimensional crystal structure consisting of distorted InO(6) octahedra, ZnO(6) octahedra, and SeO(3) polyhedra. Ga(2)Zn(TeO(3))(4) shows a three-dimensional framework structure that is composed of GaO(4) or ZnO(4) and TeO(3) polyhedra. An effect of the framework flexibility on the space group centricity is discussed. The SHG (second harmonic generation) efficiency of noncentrosymmetric Ga(2)Zn(TeO(3))(4), using 1064 nm radiation, is similar to that of KH(2)PO(4) (KDP) and is not phase-matchable (Type 1). Complete characterizations including infrared spectroscopy and thermal analyses for the reported materials are also presented, as are dipole moment calculations.