Synthesis and structure investigation of the Pb3V(PO4)3 eulytite

Lead vanadium phosphate Pb3V(PO4)3 was synthesized by solid state reaction and characterized by X-ray single crystal and powder diffraction, electron microscopy, and magnetic susceptibility measurements. The crystal structure model of Pb3V(PO4)3 was refined using X-ray single crystal data (a=10.127(1)Åa=10.127(1)Å, S.G. I4¯3d,Z=4Z=4). The compound has an eulytite-like structure and its average structure model may be presented as a three-dimensional network formed by strongly distorted mixed (Pb/VIII) metal-oxygen octahedra connected by edge sharing and forming corrugated chains. The octahedra are additionally linked by tetrahedral phosphate groups via corner sharing. Lead and vanadium atoms randomly occupy two close positions in the octahedra. The electron microscopy study revealed the presence of a rhombohedral superstructure with asup=asub×2 and csup=csub×75/2 indicating ordering in the structure. The same type of superstructure was found by us for two another lead-containing eulytite Pb3Fe(PO4)3 where Fe+3 has an ionic radius close to that of V+3. Magnetic susceptibility measurements revealed Curie–Weiss behavior for the Pb3V(PO4)3 compound.

The scheme at the left of the [1¯21¯0]s* pattern shows one of the two twins present in the [1¯21¯0]s* pattern and the indexation of this twin.Figure optionsDownload as PowerPoint slide