Mixed lone-pair and mixed anion compounds: Pb3(SeO3)(HSeO3)Br3, Pb3(SeO3)(OH)Br3, CdPb8(SeO3)4Cl4Br6 and RbBi(SeO3)F2

Four new mixed lone-pair mixed anion materials, Pb-3(SeO3)(HSeO3)Br-3, Pb-3(SeO3)(OH)Br-3, CdPb8(SeO3)(4)Cl4Br6 and RbBi(SeO3)F-2, were successfully synthesized by hydrothermal and solid-state techniques. All four compounds exhibit three-dimensional crystal structures, however the frameworks are vastly different. Pb-3(SeO3)(HSeO3)Br-3 exhibits a three-dimensional (3D) structure consisting of sheets of [PbO5Br3], [PbO4Br3] and [PbO4Br2] polyhedra linked to [SeO3] and [SeO2(OH)] groups. Pb-3(SeO3)(OH)Br-3 also exhibits a 3D framework composed of chains of edge-sharing [PbO3(OH)Br-2] and [PbO2(OH)Br-3] octahedra connected by [SeO3] groups. The 3D network of CdPb8(SeO3)(4)Cl4Br6 is composed of 1D [Pb4Br3Cl4] chains attached to [CdSe4O12] units through shared oxygens. Finally, RbBi(SeO3)F-2 exhibits a 3D network made up of sheets of corner-sharing [BiO3F4] and [SeO3] polyhedra. For all of the reported compounds, infrared spectroscopy, UV-vis diffuse reflectance spectroscopy and thermogravimetric measurements were performed.