Hexaaqua-magnesium(II) bis-{5-[3-(1H-tetra-zol-5-yl)phen-yl]tetra-zolide} tetra-hydrate.

The asymmetric unit of the title compound, [Mg(H2O)6](C8H5N8)2·4H2O, contains one half of the centrosymmetric dication, one anion and two water mol­ecules. The MgII ion is coordinated by six water mol­ecules in a slightly distorted octa­hedral geometry. In the anion, the two five-membered heterocycles are twisted from the central benzene ring by 4.34 (11) and 3.20 (10)°. In the crystal, O—H⋯N, O—H⋯O and N—H⋯O hydrogen bonds generate a three-dimensional network.