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(C(4)H(2)O(4))(C(11)H(9)N(3)O)(2)(H(2)O)](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-pyridyl­isonicotinamide (3-pina) ligands, and one apical aqua ligand, also sited on the crystallographic twofold rotation axis. The exobidentate fumarate ligands form [Cu(fumar­ate)(3-pina)(2)(H(2)O)](n) coordination polymer chains that are arranged parallel to [001]. In the crystal, these polymeric chains are anchored into supra­molecular 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.