Inorganic Chemistry, Vol.57, No.13, 7950-7956, 2018
Syntheses, Structures, and Properties of Non-Centrosymmetric Quaternary Tellurates BiMTeO6 (M = Al, Ga)
Single crystals of two new metal tellurates BiMTeO6 (M = Al, Ga) with a honeycomb layered structure were obtained by the molten flux method and characterized. The BiMTeO6 compounds both crystallize into a non-centrosymmetric trigonal space group of P312 (no. 149) with cell parameters of a = 5.0667(8) angstrom, c = 4.9920(16) angstrom and a = 5.107(3) angstrom, c = 4.932(6) angstrom, respectively. The noncentrosymmetry of BiAlTeO6 and BiGaTeO6 originates from the packing order of the octahedra. In these two structures, TeO6 octahedra and MO6 octahedra share edges and form a honeycomb open-framework with [TeMO6](infinity) layers. The layers of [MTeO6](infinity) and [BiO6](infinity) alternate and are connected along the c-axis by corner-sharing oxygen atoms to form the three-dimensional framework. The chiral compound BiGaTeO6 exhibits a powder second harmonic generation (SHG) response of similar to 0.2 times that of potassium dihydrogen phosphate (KDP) and an absorption edge of 355 nm.