Bis(2,20-bipyridyl-j2N,N0)(sulfato- j2O,O0)nickel(II) 2.5-hydrate

disorder in solvent or counterion; R factor = 0.042; wR factor = 0.124; data-to-parameter ratio = 10.0. The title compound, [Ni(SO4)(C10H8N2)2]2.5H2O, is a nickel(II) complex with a distorted octahedral coordination geometry. The NiII atom is bonded by two O atoms of the bidentate chelating sulfate ligand and the four N atoms of two chelating 2,20-bipyridine ligands. The Ni—N bond lengths range from 2.059 (3) to 2.075 (3) A ̊ and the Ni—O bond lengths are 2.098 (3) and 2.123 (3) Å. The bipyridyl ligands are both close to planar (r.m.s. deviations of 0.254 and 0.0572 Å) and are almost orthogonal, making a dihedral angle of 82.77 (1). In the crystal, the complex and water molecules are connected by O—H O hydrogen bonds. Interestingly, six water molecules form a chain linking two complex molecules via sulfate O atoms. There are also stacking interactions between the aromatic rings of neighbouring 2,20-bipyridine ligands with shortest non-covalent contacts of 3.268 (6), 3.393 (6) and 3.435 (5) Å. One of the three unique water molecules shows half-occupation. Related literature For applications of the 2,20-bipyridyl ligand, see: Fritsky et al