Poly[[(4,4'-bipyridine-κN)[μ(3)-(S)-2-hy-droxy-butane-dioato-κO,O:O:O]zinc] dihydrate]

In the title compound, {[Zn(C(4)H(4)O(5))(C(10)H(8)N(2))]·2H(2)O}(n), the Zn(II) ion displays a distorted tetra-gonal-pyramidal coordination environment with one hy-droxy O and three carboxyl-ate O atoms from three malate anions, and the one remaining position occupied by an N atom from a 4,4'-bipyridine ligand. The pyridine rings of the 4,4'-bipyridine ligand are twisted with respect to each other by a dihedral angle of 35.8 (2)°. The uncoordinated water mol-ecules are linked to the complex mol-ecules by O-H⋯O hydrogen bonds. Each malate anion forms four coordination bonds with three Zn atoms, establishing a layer structure parallel to the ac plane. Adjacent layers are further linked via O-H⋯N hydrogen bonding. π-π stacking between the pyridine rings [face-to-face distance = 3.651 (3) Å] occurs in the crystal structure.