Phase Transitions in the Na3M2(PO4)2F3 Family (M=Al3+, V3+, Cr3+, Fe3+, Ga3+): Synthesis, Thermal, Structural, and Magnetic Studies

A new series of palladium (II) fluorides has been prepared. The A2PdF6 compounds crystallize in the orthorhombic space group Cmca. The structure of Ba2PdF6 (a=17.09(2) ?, b=6.163(2) ?, c=6.158(1) ?, Z=4) has been refined from single crystal data to conventional R1=0.0325 (wR2=0.0948) for 661 independent reflections. A Rietveld analysis of BaSrPdF6 and refinement of the lattice parameters of Pb2PdF6 have confirmed the same cationic distribution. PdII ions are fourfold-coordinated to fluorine. The isolated [PdF4]2- square-planes form layers, perpendicular to the a-axis, interleaved by bilayers of [AF8]6- antiprisms.