LAUSR

The structure of hexaaquanickel(II) bis(3-carboxy-4-hydroxybenzenesulfonate) dihydrate consists of alternating layers of inorganic cations and organic anions linked by O—H⋯O hydrogen bonds that also include non-coordinated water molecules of crystallization. The structure of hexaaquacobalt(II) bis(3-carboxybenzenesulfonate) dihydrate is also built of alternating layers of complex cations and organic anions without direct coordination to the metal by the protonated carboxylate or unprotonated sulfonate groups. A robust O—H⋯O hydrogen-bonding network involving primarily the coordinated and non-coordinated water molecules and sulfonate groups directs the packing.