Diaquabis(1,3-propanediamine)nickel(II) squarate tetrahydrate

The asymmetric unit of the title compound, [Ni(C3H10N2)2(H2O)2](C4O4)·4H2O, contains one-half of the diaquabis(1,3-propanediamine)nickel(II) cation, one-half of the centrosymmetric squarate anion and two uncoordinated water molecules. In the cation, the NiII atom is located on a crystallographic inversion centre and has a slightly distorted octahedral coordination geometry. The six-membered chelate ring adopts a chair conformation. O—H...O hydrogen bonds link the cation and anion through the water molecule, while N—H...O hydrogen bonds link the cation and anion and cation and water molecules. In the crystal structure, intermolecular O—H...O and N—H...O hydrogen bonds link the molecules into a three-dimensional network structure.