Poly[[tetraaqua(mu(7)-pyridine-2,3,5,6-tetracarboxylato)dicadmium(II)] monohydrate]

The title compound, {[Cd-2(C9HNO8)(H2O)(4)]center dot H2O}(n), consists of two crystallographically independent Cd-II cations, one tetrabasic pyridine-2,3,5,6-tetracarboxylate (pdtc) anion, four coordinated water molecules and one solvent water molecule. The Cd-II cations have distorted square-antiprismatic (one pyridine N, six carboxylate O and one water O atom) and octahedral (three carboxylate O and three water O atoms) coordination environments. Each pdtc ligand employs its pyridine and carboxylate groups to chelate and bridge seven Cd-II cations. The square-antiprismatic coordinated Cd-II cations are linked by pdtc ligands into a lamellar framework structure, while the octahedral coordinated Cd-II cations are bridged by the mu(2)-carboxylate O atoms and the pdtc ligands into a chain network that further joins neighbouring lamellae into a three-dimensional porous network. The cavities are filled with solvent water molecules that are linked to the host through complex hydrogen bonding.