Poly[[aqua-μ(6)-benzene-1,2,3-tricarboxyl-ato-μ(3)-hydroxido-dizinc] hemihydrate].

In the title compound, {[Zn(2)(C(9)H(3)O(6))(OH)(H(2)O)]·0.5H(2)O}(n), there are three independent Zn(II) atoms present; two are located on special positions, viz a twofold rotation axis and an inversion centre, and the third is located in a general position. The Zn(II) atom on the inversion centre is six-coordinated by four O atoms from four different benzene-1,2,3-tricarboxyl-ate anions and two OH(-) anions. The Zn(II) atom located on a twofold axis is four coordinated by two O atoms from two different benzene-1,2,3-tricarboxyl-ate anions and two OH(-) anions. The third Zn(II) atom, located in a general position, is five coordinated by three O atoms from three different benzene-1,2,3-tricarboxyl-ate anions, one OH(-) anion and one water mol-ecule. Each benzene-1,2,3-tricarboxyl-ate anion bridges six Zn(II) atoms, and the OH(-) anion bridges three Zn(II) atoms, resulting in the formation of a three-dimensional framework. A series of O-H⋯O hydrogen bonds involving the benzene-1,2,3-tricarboxyl-ate anions, the OH(-) anion and the coordinating and the two water solvent mol-ecules further stablize the crystal structure. The two solvent water molecules show occupancies of 0.5 and 0.25.