Crystal Structure of New Mixed Potassium-Erbium Chloro-Cyclo-triphosphate Trihydrate, ErK₄(P₃O₉)₂Cl·3H₂O

Abstract

The title compound is the first rare-earth cyclo-triphosphate involving a chlorine ion to be reported. It crystallizes in the hexagonal space group P6₃/m with a = 9.9366(3)Å, c = 12.1601(5)Å, Z = 2, V = 1039.78(6)ų and D_x = 2.833 g cm^-3. The crystal structure was solved by the direct method and refined using successive Fourier analysis to R = 0.0349 for 1042 reflections. It consists of P₃O₉ rings lying in (0 0 1) planes, interconnected by Er and K polyhedra along the c axis. The water molecule takes part into Er and K(1) coordination polyhedra.