Synthesis, Structure, and Properties of BaVO2(AsO4):  a New Vanadium Arsenate Containing the V2O42+ Core

The new vanadium arsenate BaAsVO6 has been synthesized hydrothermally and structurally characterized by single-crystal X-ray diffraction, IR spectroscopy, and magnetic susceptibility measurements. It crystallizes in the monoclinic system, space group P21/c with unit cell parameters a = 5.645(1) A, b = 10.243(1) A, c = 8.945(1) A, β = 90.60(1)°, and Z = 2. The layered structure is built up from V2O42+ units and AsO43- anions, the AsO43- ligands being coordinated to two (V2O4)2+ units in both, terminal and bridging μ2-AsO43- fashion. The [VO2(AsO4)]2- layers are separated by Ba2+ cations. The V2O42+ unit has no precedence in oxo-vanadium chemistry.