Erbium cyclo-hexaphosphate decahydrate: Er2P6O18 · 10H2O

Crystal data and atomic arrangement are given for a new rare-earth cyclo-hexaphosphate decahydrate: Er2P6O18 · 10H2O. This compound is monoclinic P21a, with a = 18.315(8), b = 13.343(4), c = 11.211(4) Å, b = 94.46(3)⊃, Z = 4, V = 2681 (3) Å3. The crystal structure was determined with a final R = 0.032 for 4897 independent reflections. It can be described as a succession of thick corrugated layers of alternated P6O18 rings and ErO8 polyhedra with wide channels where non-bonded water molecules are located. The phosphoric ring anion has no internal symmetry. The erbium polyhedra do not share any edge or corner.