Tetra-aqua-bis(nicotinamide-κN ¹)nickel(II) bis-(2-fluoro-benzoate)

The asymmetric unit of the title complex, [Ni(C₆H ₆N₂O)₂(H₂O)₄](C ₇H₄FO₂)₂, contains one-half of the complex cation with the Ni^II atom located on an inversion center, and a 2-fluoro-benzoate (FB) counter-anion. The four O atoms in the equatorial plane around the Ni atom form a slightly distorted square-planar arrangement with an average Ni- O bond length of 2.079 Å, and the slightly distorted octa-hedral coordination is completed by the two N atoms of the nicotinamide (NA) ligands in the axial positions. The dihedral angle between the carboxyl group and the attached benzene ring is 28.28 (11)°, while the pyridine and benzene rings are oriented at a dihedral angle of 8.31 (4)°. In the crystal structure, O- H⋯O, N- H⋯O, C- H⋯O, and C- H⋯F hydrogen bonds link the mol-ecules into a three-dimensional network. π-π Contacts between the pyridine and benzene rings [centroid-centroid distance = 3.626 (1) Å] may further stabilize the crystal structure. The 2-fluoro-benzoate anion is disordered over two orientations, with an occupancy ratio of 0.85:0.15.