Neue Oxopnictate AI 3MVO4: Darstellung und Kristallstruktur von A3AsO4 (A = K, Rb, Cs) und K3BiO4 / New Oxopnictates AI 3MVO4: Synthesis and Crystal Structure of A3AsO4 (A = K, Rb, Cs) and K3BiO4

Abstract

Abstract The title compounds have been synthesized via oxidation of the elemental pnicogenes (M = As, Bi) with the hyperoxides AO2 (A = K, Rb, Cs) and their crystal structures were determined on the basis of single crystal X-ray data. In K3AsO4 (orthorhombic, Cccm, a = 1060:1(1), b = 1135:2(1), c = 1694:0(2) pm, Z = 16) and Cs3AsO4(orthorhombic, Pnma, a = 1254:3(2), b = 902:9(2), c = 658:5(3) pm, Z = 4) isolated tetrahedra [AsO4]3- with distances As-O between 167.0 and 170.5 pm are present, which are arranged in a nearly cubic close packing. The structure of K3BiO4 (triclinic, P1̄, a = 643:18(6), b = 657:27(6), c = 762:41(7) pm, α = 101:724(2)°, β = 96:472(2)°, γ = 105:465(2)°, Z = 2) contains centrosymmetric dimers [O3BiO2BiO3]6-, in which the Bi(V) atoms are surrounded by five O atoms in a distorted trigonal bipyramidal geometry with distances Bi-O in the range of 199.5 to 233.1 pm.