RbGa3(P3O10)2:: a new gallium phosphate isotypic with RbAl3(P3O10)2

Rubidium trigallium bis(triphosphate), RbGa3(P3O10)(2) has been synthesized by solid-state reaction and studied by single-crystal X-ray diffraction at room temperature. This compound is the first anhydrous gallium phosphate containing both GaO4 tetrahedra (Gal) and GaO6 octahedra (Ga2 and Ga3). The three independent Ga atoms are located on sites with imposed symmetry 2 (Wickoff positions 4 alpha for Gal and 4b for Ga2 and Ga3). The GaO4 and GaO6 polyhedra are connected through the apices to triphosphate groups and form a three-dimensionnal host lattice. This framework presents intersecting tunnels running along the [001] and <110> directions, where the Rb2+ cations are located on sites with imposed symmetry 2 (Wickoff position 4a). The structure also exhibits remarkable features, such as infinite helical columns created by the junction of GaO4 and PO4 tetrahedra.