Investigation of New Alkali Bismuth Oxosulfates and Oxophosphates with Original Topologies of Oxo-Centered Units

Two new alkali bismuth oxosulfates, [Bi12O15]­Li2(SO4)4 (I) and [Bi7K2O8]­K­(SO4)4 (II), have been synthesized by heating a mixture of Bi2O3, CuSO4­5H2O, and A2CO3 (A = Li, K), and characterized by single crystal XRD, transmission electron microscopy, and multiphoton SHG and IR spectroscopy. In the above formula the [BixOy] subunits denote the 3D-porous (I) or 1D-columnar (II) polycationic host-lattice formed of edge-sharing OBi4 or O­(Bi,K)4 oxocenterd tetrahedra. The SO42– groups and alkali ions are arranged into channels in the interstices leading to original opened crystal structures for these two first reported alkali oxo-bismuth sulfates. The strong adaptability of the oxocentered framework is demonstrated by the possibility of preparing single crystals of [Bi8.73K0.27O8]­K1.54(PO4)4 (III) whose crystal structure is similar to those of II with disorder between OBi4 and O­(Bi3,K) tetrahedra and different channel occupancy due to the aliovalent replacement of SO42– for PO43–.