Zn2(VO4)(IO3): A Novel Polar Zinc(II) Vanadium(V) Iodate with a Large SHG Response

The synthesis, crystal and electronic structures, and optical properties of the first zinc­(II) vanadium­(V) iodate, namely, Zn2(VO4)­(IO3), are reported. Zn2(VO4)­(IO3) crystallizes in the noncentrosymmetric (NCS) and polar space group Pc (No. 7) with a = 5.2714(8) Å, b = 10.0402(11) Å, c = 5.5070(8) Å, β = 101.326(10)°, and Z = 2. It displays a novel three-dimensional (3D) network structure composed of ZnO5, ZnO6, VO4, and IO3 polyhedra. One-dimensional (1D) chains of edge-sharing ZnO5 polyhedra and 1D chains of corner-sharing ZnO6 octahedra along the c-axis are interconnected via corner-sharing into a two-dimensional (2D) zinc oxide layer, and such layers are bridged by both VO4 tetrahedra and IO3 groups into a 3D network. The polarity in the structure is imparted by the alignment of the stereochemically active lone pairs of the iodate anions along the c-axis. The second harmonics generation (SHG) measurements on powder samples of Zn2(VO4)­(IO3) under 1064-nm laser radiation revealed a large response of ∼6 × KDP, which is Type I phase-matchable. Thermal stability and optical properties, as well as theoretical calculations based on DFT methods, were also performed.