Synthesis, crystal structure and Hirshfeld surface analysis of tetra­aqua­bis­(isonicotinamide-κN (1))cobalt(II) fumarate

The reaction of cobalt(II) with fumaric acid (H(2)fum) and isonicotinamide in a basic solution produces the title salt, [Co(C(6)H(6)N(2)O)(2)(H(2)O)(4)](C(4)H(2)O(4)). In the complex cation, the Co(II) atom, located on an inversion centre, is coordinated by two isonicotinamide and four water mol­ecules in a distorted N(2)O(4) octa­hedral geometry. The fumarate anion is located on another inversion centre and is linked to neighbouring complex cations via O—H⋯O and N—H⋯O hydrogen bonds and weak C—H⋯O hydrogen bonds. In the crystal, the complex cations are further linked by O—H⋯O, N—H⋯O and weak C—H⋯O hydrogen bonds, forming a three-dimensional supra­molecular architectecture. Hirshfeld surface analyses (d (norm) surfaces and two-dimensional fingerprint plots) for the title compound are presented and discussed.