catena-Poly[[[tetra­kis­(4-methyl­pyridine-κN)copper(II)]-μ-sulfato-κ2 O:O′] 4.393-hydrate]

The structure of the title compound, {[Cu(SO(4))(C(6)H(7)N)(4)]·4.393H(2)O}(n), consists of Cu(2+) ions surrounded in a square-planar fashion by 4-methyl-pyridine ligands, forming two crystallographically independent Cu{H(3)C(C(5)H(4)N)}(4) units that are both located on crystallographic inversion centers. The Cu(4-methyl-pyridine)(4) units are, in turn, connected with each other via bridging sulfate anions, leading to the formation of infinite [Cu{H(3)C(C(5)H(4)N)}(4)SO(4)](n) zigzag chains along [001]. The completed coordination spheres of the Cu(2+) ions are slightly distorted octa-hedral. The axial Cu-O bonds are elongated [average length = 2.42 (4) Å] compared to the equatorial Cu-N bonds [average length = 2.043 (2) Å]. The inter-stitial space between the chains is filled with uncoordinated water mol-ecules that consolidate the structure through O-H⋯O hydrogen bonding. One of the five crystallographically independent solvent water mol-ecules is partially occupied with an occupancy factor of 0.396 (4). Due to hydrogen bonding between symmetry-equivalent water mol-ecules across inversion centers, several of the water H atoms are disordered in 1:1 ratios over mutually exclusive positions. The crystal under investigation was found to be non-merohedrally twinned in a 0.789 (1):0.211 (1) ratio by a 180° rotation around the reciprocal b axis.