Poly[[dodeca­aqua­(μ₄-benzene-1,4-dicarboxyl­ato)(μ₂-4,4′-bipyridine-κ²N:N′)dicerium(III)] bis­(benzene-1,4-dicarboxyl­ate)]

The asymmetric unit of the title compound, {[Ce₂(C₈H₄O₄)(C₁₀H₈N₂)(H₂O)₁₂](C₈H₄O₄)₂}_n, consists of half a Ce^III cation, a quarter of a coordinated benzene-1,4-dicarboxyl­ate (bdc²⁻) dianion, a quarter of a 4,4′-bipyridine (bpy) mol­ecule, three water mol­ecules and a half of an uncoordinated benzene-1,4-dicarboxyl­ate dianion. The Ce^III ion is located on a twofold rotation axis and exhibits a distorted trigonal prism square-face tricapped coordination geometry. The coordinated and uncoordinated bdc²⁻ ions and the bpy mol­ecule lie about special positions of site symmetries 2/m, m and 2/m, respectively. The Ce^III ions are bridged by the bdc²⁻ and bpy ligands, giving a sheet structure parallel to the ac plane. The uncoordinated bdc²⁻ dianion exists between the sheets and links the sheets by inter­molecular O—H...O hydrogen bonds between the uncoordinated bdc²⁻ and coordinated water mol­ecules. A π–π stacking inter­action between the uncoordinated bdc²⁻ dianion and the bpy ligand [centroid–centroid distance = 3.750 (4) Å] is also observed.