New lead vanadium phosphate with langbeinite-type structure: Pb1.5V2(PO4)3

The new lead vanadium phosphate Pb1.5V2(PO4)3 was synthesized by solid state reaction and characterized by X-ray powder diffraction, electron microscopy, and magnetic susceptibility measurements. The crystal structure of Pb1.5V2(PO4)3 (a = 9.78182(8) Å, S.G. P213, Z = 4) was determined from X-ray powder diffraction data and belongs to the langbeinite-type structures. It is formed by corner-linked V3+O6 octahedra and tetrahedral phosphate groups resulting in a three-dimensional framework. The lead atoms are situated in the structure interstices and only partially occupy their positions. An electron microscopy study confirmed the structure solution. Magnetic susceptibility measurements revealed Curie–Weiss (CW) behavior for Pb1.5V2(PO4)3 at high temperature whereas at around 14 K an abrupt increase on the susceptibility was observed.