RESUMEN
The title compound, [Ba(C12H6O4)(H2O)2] n , is represented by a layer-like structure built of BaO8 polyhedra. The asymmetric unit contains a Ba(2+) ion, half a coordinating water mol-ecule and half a µ4-bridging naphthalene-1,8-dicarboxyl-ate (1,8-nap) ligand, the whole structure being generated by twofold rotational symmetry. The carboxyl-ate groups of the 1,8-nap ligands act as bridges linking four Ba(2+) ions, while each Ba(2+) ion is eight-coordinated by O atoms from four 1,8-nap ligands and two coordinating water mol-ecules. In the crystal, there are O-Hâ¯O hydrogen bonds involving the water mol-ecules and carboxyl-ate O atoms in the BaO8 polyhedra. Each BaO8 polyhedron is connected via corner-sharing water O atoms or edge-sharing ligand O atoms, forming a sheet parallel to the bc plane. These sheets stack along the a-axis direction and are connected via van der Waals forces only. The naphthalene groups protrude above and below the layers of the BaO8 polyhedra and there are voids of ca 208â Å(3) bounded by these groups. No residual electron density was found in this region. The crystal studied was twinned by pseudo-merohedry, with a refined twin component ratio of 0.5261â (1):0.4739â (1).
RESUMEN
The asymmetric unit of the title compound, {[MgNa2(C10H4O8)2(H2O)8]·2H2O}(n), contains one octa-hedrally coordin-ated Mg(II) atom (site symmetry 2/m), one octahedrally coordinated Na(I) atom (site symmetry 2) and one half of the dihydrogen benzene-1,2,4,5-tetra-carboxyl-ate (btec) ligand, the second half of the ligand being generated by a twofold rotation axis. The basic framework of the title compound features infinite (-Na-Na-Mg-)(n) chains along [10-1] with the metal cations bridged by the coordinating water molecules. The chains are isolated from each other by µ4-bridging btec ligands, which form inter-molecular O-Hâ¯O hydrogen bonds to uncoordinated water mol-ecules and the coordinated water mol-ecules of a neighbouring chain. In each btec ligand, there are also intramolecular O-Hâ¯O hydrogen bonds.
RESUMEN
The title compound, rubidium ditin(IV) tris-(phosphate), RbSn(2)(PO(4))(3), belongs to the NASICON-type family of phosphates and crystallizes in the space group R[Formula: see text]. The structure is composed of PO(4) tetra-hedra (1 symmetry) and two slightly distorted SnO(6) octa-hedra, both with 3. symmetry, which are inter-linked through corner-sharing O atoms to form a (3) (∞)[Sn(2)(PO(4))(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.