New open-framework phosphate and phosphite compounds of gallium

Five new open-framework compounds of gallium have been synthesized by hydrothermal methods and their structures determined by single crystal X-ray diffraction studies. The compounds, [C8N4H26][Ga6F4(PO4)6], I, [C5N3H11][Ga3F2(PO4)3]·H2O, II, [C6N3H19][Ga4(C2O4)(PO4)4(H2PO4)]·2H2O, III, [Ga2F3(HPO4)(PO4)]·2H3O, IV, and [C3N2H5]2[Ga4(H2O)3(HPO3)7], V, possess three-dimensional structures. All the compounds are formed by the connectivity between the Ga polyhedra and phosphite/phosphate units. The observation of SBU-6 (I and II) and spiro-5 (IV) secondary building units (SBUs) are noteworthy. The flexibility of the formation of gallium phosphate frameworks has been established by the isolation of two related structures (I and II) from the same SBU units but different organic amines. Some of the present structures have close resemblance to the gallium phosphate phases known earlier. The compounds have been characterized by CHN analysis, powder XRD, IR, and TGA.