Poly[ethylenediaminium [di-μ-aqua-(μ6-benzene-1,2,4,5-tetracarboxylato-κ10O1,O1′:O2,O2′:O2′:O4,O4′:O5:O5,O5′)dithallium(I)]]

The title compound, {(C2H10N2)[T1(2)(C10H2O8)(H2O)(2))]}(n), was prepared using (enH(2))(2)(btc)center dot 2H(2)O and thallium(I) nitrate (en = ethylenediamine and btcH(4) = benzene-1,2,4,5- tetracarboxylic acid). The enH(2) cation and btc ligand are each located on an inversion centre. The T1(I) atom is seven-coordinated by three btc ligands and two water molecules in an irregular geometry due to the stereochemically active lone pair on the T1 centre. The water molecule and btc ligand are bonded to the T1 atoms in mu- and mu(6)- forms, respectively, leading to a three-dimensional structure. The crystal structure involves O-H center dot center dot center dot O, N-H center dot center dot center dot O and C-H center dot center dot center dot O hydrogen bonds, and also a T1 center dot center dot center dot pi interaction of 3.537 (1) angstrom.