Structural patterns and dimensionality in magnesium borophosphates: The crystal structures of Mg2(H2O)[BP3O9(OH)4] and Mg(H2O)2[B2P2O8(OH)2]·H2O

Abstract

Hydrothermal investigations in the system MgO/B2O3/ P2O5(/H2O) yielded two new magnesium borophosphates, Mg-2(H2O)[BP3O9(OH)(4)] and Mg(H2O)(2)[B2P2O8(OH)(2)]center dot H2O The crystal structures were solved by means of single crystal X-ray diffraction. While the acentric crystal structure of Mg-2(H2O)[BP3O9(OH)(4)] (orthorhombic, P2(1)2(1)2(1) (No. 19), a = 709.44(5) pm, b = 859.70(4) pm, c = 1635.1(1) pm, V = 997.3(3) x 10(6) pm(3), Z = 4) contains 1D infinite chains of magnesium coordination octahedra interconnected by a borophosphate tetramer, Mg(H2O)(2)[B2P2O8(OH)(2)]center dot H2O (monoclinic, P2(1)/c (No. 14), a = 776.04(5) pm, b = 1464.26(9) pm, c = 824.10(4) pm, beta = 90.25(1)degrees, V = 936.44(9) x 10(6) pm(3), Z = 4) represents the first layered boro-phosphate with 6(3) net topology. The structures are discussed and classified in terms of structural systematics.