Chemical Vapor Transport Synthesis of Cu(VO) 2 (AsO 4 ) 2 With Two Distinct Spin-1/2 Magnetic Ions.

A new copper vanadyl arsenate, Cu(VO) 2 (AsO 4 ) 2 , was synthesized via the chemical vapor transport method. Cu(VO) 2 (AsO 4 ) 2 adopts an original structure type. It is characterized by layers formed by edge-sharing and corner-sharing V-centered octahedra resulting in a unique topology that was hitherto not reported for vanadates. Single CuO 6 octahedra connect vanadate layers into a rigid framework. The thermal expansion of the framework studied by the single-crystal HT X-ray diffraction is reported. The magnetic behavior of Cu(VO) 2 (AsO 4 ) 2 shows an interplay of ferromagnetic V 4+ -V 4+ and antiferromagnetic Cu 2+ -V 4+ interactions that result in a ferrimagnetic long-range order below T C = 66 K.