Novel Polyanionic Topologies in Ag2VAsO6 and Ag6V2As2O13

Abstract

Two new silver vanadate arsenates, Ag2VAsO6 and Ag6V2As2O13, have been prepared applying high oxygen pressure syntheses in stainless-steel autoclaves. Ag2VAsO6 crystallizes in space group P1 with unit cell parameters a=639.1(1), b=646.1(1), c=706.6(1) pm, α =116.105(3), ß =91.759(4), γ = 90:067(4)°, and Z =2 (R1 =0.058, 3935 independent reflections). The structure consists of AsO4 tetrahedra and VO6 octahedra which are linked to form two-dimensional 2 ¥[VAsO6]2- polyanions, separated by silver cations. Ag6V2As2O13 (C2=c, a=1895.9(2), b=536.40(6), c=1308:5(2) pm, ß =113:578(2)°, Z =4; R1 =0.030, 2571 independent reflections) displays as primary building units AsO4 tetrahedra and VO5 trigonal bipyramids which are condensed by sharing edges to one-dimensional 1 ¥[V2As2O13]6- ladder-like strands, set apart by the silver cations. These heteropolyanions are without precedent