catena-Poly[[aquabis[N-(pyridin-3-yl)isonicotinamide-κN (1)]copper(II)]-μ-fumarato-κ(2) O (1):O (4)].

In the title compound, [Cu(C4H2O4)(C11H9N3O)2(H2O)] n , Cu(II) ions on crystallographic twofold rotation axes are coordinated in a square pyramidal environment by two trans O atoms belonging to two monodentate fumarate anions, two trans isonicotinamide pyridyl N-donor atoms from monodentate, pendant 3-pyridyl-isonicotinamide (3-pina) ligands, and one apical aqua ligand, also sited on the crystallographic twofold rotation axis. The exobidentate fumarate ligands form [Cu(fumar-ate)(3-pina)2(H2O)] n coordination polymer chains that are arranged parallel to [001]. In the crystal, these polymeric chains are anchored into supra-molecular layers parallel to (100) by O-H⋯O hydrogen bonds between aqua ligands and unligating fumarate O atoms, and N-H⋯O(=C) hydrogen bonds between 3-pina ligands. In turn, the layers aggregate by weak C-H⋯N and C-H⋯O hydrogen bonds, affording a three-dimensional network.