Poly[Tetraaquabis(Mu(4)-Thiophene-2,5-Dicarboxylato)(Mu(2)-Thiophene-2,5 -Dicarboxylato) Dieuropium(Iii)]

The three-dimensional coordination polymer, [Eu-2(C6H2O4S) (3)(H2O)(4)](n), has been synthesized under hydrothermal conditions. The asymmetric unit comprises one Eu3+ cation, two aqua ligands and one and a half thiophene-2,5-dicarboxylate anions (the half-anion being completed by a twofold rotation axis). The Eu3+ cation is eight-coordinated in a distorted dodecahedral geometry. The crystal structure features O-H center dot center dot center dot O hydrogen bonds.