RbSn2(PO4)3, a NASICON-type phosphate

The title compound, rubidium ditin(IV) tris­(phosphate), RbSn2(PO4)3, belongs to the NASICON-type family of phosphates and crystallizes in the space group R . The structure is composed of PO4 tetra­hedra (1 symmetry) and two slightly distorted SnO6 octa­hedra, both with 3. symmetry, which are inter­linked through corner-sharing O atoms to form a 3 ∞[Sn2(PO4)3]− framework. The Rb+ cations are located on threefold inversion axes in the voids of this framework and exhibit a coordination number of 12. The crystal studied was twinned by merohedry with a component ratio of 0.503:0.497

Rb2Sb4O11

The title compound, dirubidium tetraantimonate(V), Rb2Sb4O11, has been synthesized by flux reaction. It is isotypic with known A2Sb4O11 (A = K, Cs) structures and consists of an (Sb4O11)2- skeleton and two Rb atoms as charge-compensating cations. Distorted SbO6 octahedra share edges and corners, resulting in a layered assembly. Alternate stacking of the layers along the c axis leads to the formation of tunnels. The Rb+ ions, surrounded by nine and ten O atoms, respectively, are located in these tunnels. Some atoms in the structure are on special positions of m symmetry (two Sb atoms, both Rb atoms and four O atoms) and 2 symmetry (one O atom