HYDROTHERMAL SYNTHESIS AND CRYSTAL-STRUCTURES OF BA2FE3H(PO4)2(P2O7)2 AND BA2V3H(PO4)2(P2O7)2

Two new FeIII and VIII phosphates, Ba2Fe3H(PO4)2(P2O 7)2 and Ba2V3H(PO4)2(P2O 7)2, have been prepared and their structures have been determined from single-crystal X-ray diffraction data. They crystallize in the triclinic space group P1#x0304; with a = 4.858(2), b = 7.908(2), c = 11.300(3) Å, α = 89.10(2), β = 89.28(2), γ = 87.25(2)°, V = 433.5(3) Å3, Z = 1 and R = 0.0195 for Ba2Fe3H(PO4)2(P2O 7)2, and a = 4.8433(8), b = 7.902(1), c = 11.308(2) Å, α = 88.77(1), β = 89.22(1), γ = 87.11(1)°, V = 432.09(12) Å3Z = 1 and R = 0.020 for Ba2V3H(PO4)2(P2O 7)2. The two compounds are isostructural. The framework is built up from corner-sharing MIIIO6 octahedra, PO4 tetrahedra and P2O7 units. The structure contains tunnels along the [100] direction in which the Ba2+ ions are located. © 1993 Academic Press, Inc.