Synthesis and characterization of a cadmium germanium phosphate CdGe(OH)3PO4 with an open framework

A new three-dimensional (3D) framework cadmium germanium phosphate, CdGe(OH)3PO4 was synthesized by solvothermal methods. The crystal structure of CdGe(OH)3PO4 was established by single-crystal X-ray diffraction: CdGeH3O7P, Orthorhombic, Cmca, a=7.1415(7) Å, b=10.9034(1) Å, c=13.1098(1) Å, Z=8, R1=0.0365 (F2>2σ(F2) and wR2=0.0985 (all data). The framework of CdGe(OH)3PO4 is built by a mixed network of GeO6, CdO6 octahedra and PO4 tetrahedra, which are linked to form a 3-membered ring (3-MR). The GeO6 and CdO6 octahedra share common vertexes and edges, respectively, to form one-dimensional (1D) Ge–O–Ge and Cd–O–Cd chains, which are further connected forming corrugated Ge–O–Cd layers. The layers are linked by PO4 tetrahedra, leading to a 3D open-framework structure with 3- and 6-MR channels.