Tetra-aqua(2,2'-bipyridine-κN,N')magnesium(II) bis-(4-bromo-benzoate).

In the complex cation of the title compound, [Mg(C(10)H(8)N(2))(H(2)O)(4)](C(7)H(4)BrO(2))(2), the Mg(II) atom is coordinated by two N atoms from a 2,2'-bipyridine ligand and four water O atoms in a distorted MgN(2)O(4) octa-hedral geometry. The cation is located on a special position on a twofold rotation axis which passes through the Mg(II) atom and the centroid of the 2,2'-bipyridine ligand. The 2,2'-bipyridine ligands exhibit nearly perfect coplanarity (r.m.s. deviation = 0.0035 Å) . In the crystal, O-H⋯O and C-H⋯O, C-H⋯Br hydrogen bonds and π-π stacking inter-actions [mean inter-planar distance of 3.475 (6) Å between adjacent 2,2'-bipyridine ligands] link the cations and anions into a three-dimensional supra-molecular network. One Br atom is disordered over two sites with occupancy factors of 0.55 and 0.45.