Three new d10 transition metal selenites containing PO4 tetrahedron: Cd7(HPO4)2(PO4)2(SeO3)2, Cd6(PO4)1.34(SeO3)4.66 and Zn3(HPO4)(SeO3)2(H2O)

Three new d 10 transition metal selenites containing PO 4 tetrahedron, namely, Cd 7 (HPO 4 ) 2 (PO 4 ) 2 (SeO 3 ) 2 ( 1 ), Cd 6 (PO 4 ) 1.34 (SeO 3 ) 4.66 ( 2 ) and Zn 3 (HPO 4 )(SeO 3 ) 2 (H 2 O) ( 3 ), have been synthesized by hydrothermal reaction . They feature three different structural types. Compound 1 exhibits a novel 3D network composed of 3D cadmium selenite open framework with phosphate groups filled in the 1D helical tunnels. The structure of compound 2 displays a new 3D framework consisted of 2D cadmium oxide layers bridged by SeO 3 and PO 4 groups. Compound 3 is isostructural with the reported solids of Co 3 (SeO 3 ) 3-x (PO 3 OH) x (H 2 O) when x is equal to 1.0. Its structure could be viewed as a 3D zinc oxide open skeleton with SeO 3 and HPO 4 polyhedra attached on the wall of the tunnels. They represent the only examples in metal selenite phosphates in addition to the above cobalt compounds. Optical diffuse reflectance spectra revealed that these solids are insulators, which are consistent with the results of band structure computations based on DFT algorithm.