Diaqua­bis­(2-hy­droxy­benzoato-κO 1)bis­(nicotinamide-κN 1)cadmium–diaqua­bis­(2-hy­droxy­benzoato-κ2 O 1,O 1′)(nico­tin­amide-κN)cadmium–water (1/2/4)

The crystal structure of the title compound, [Cd(C7H5O3)2(C6H6NO)2(H2O)2]·2[Cd(C7H5O3)2(C6H6NO)(H2O)2]·4H2O, consists of two kinds of Cd(II) complexes (A and B) and lattice water mol-ecules. In complex A, [Cd(C7H5O3)2(C6H6NO)2(H2O)2], the Cd(II) cation is located on an inversion center and is coordinated by two salicylate anions, two nicotinamide (NA) ligands and two water mol-ecules in a slightly distorted octa-hedral geometry. In complex B, [Cd(C7H5O3)2(C6H6NO)(H2O)2], the Cd(II) cation is coordinated by two salicylate anions, one nicotinamide (NA) ligand and two water mol-ecules in an irregular seven-coordinate geometry. There are extensive intra-molecular O-H⋯O and weak C-H⋯O hydrogen bonds as well as extensive inter-molecular O-H⋯O and N-H⋯O hydrogen bonding in the crystal structure. π-π stacking between the pyridine and benzene rings, between the benzene rings, between the benzene and pyridine rings and between the pyridine rings [centroid-centroid distances = 3.5989 (10), 3.6005 (10), 3.5800 (9) and 3.5205 (10) Å, respectively] further stabilize the crystal structure. A weak N-H⋯π inter-action also occurs. One of the lattice water mol-ecules is disordered over two positions with an occupancy ratio of 0.70:0.30.