Synthesis and structures of two open-framework manganese phosphate-silicates

Two new manganese phosphate-silicates Na3Mn2Si2PO10, (1), and CsNag[Mn53+Mn0.82+center dot Si12O32.6(OH)(5.4)](PO4)(H2O)(4) (2) were synthesized under mild hydrothermal conditions. The structure of 1 contains Si4O12 vierer single rings that interconnect chains of MnO6 octahedra to form slabs. The slabs are cross-linked by PO4 tetrahedra to form a framework with channels filled by sodium ions. Compound 2 consists of silicate single layers that are interconnected by complex chains of MnO, polyhedra to form a 3D framework. The framework has channel systems filled by Na+, Cs+, (PO4)(3-) ions and water molecules. The silicate single layer of 2 is an unbranched sechser single layer and contains both secondary Q(2) and tertiary Q(3) tetrahedra with a Q(2)/Q(3) ratio 2:1. The valence states of the Mn atoms in 2 are derived from bond valence calculations and are supported by XPS measurement.