The three-dimensional intermolecular network formed via water molecules in trans-bis(nitrito-κN)tetrakis(pyridine-κN)ruthenium(II) dihydrate.

The molecular geometry of the tetragonal crystal structure of the title compound, [Ru(NO(2))(2)(C(5)H(5)N)(4)]·2H(2)O, differs from that previously determined by powder diffraction [Schaniel et al. (2010). Phys. Chem. Chem. Phys. 12, 6171-6178]. In the [Ru(NO(2))(C(5)H(5)N)(4)] molecule, the Ru atom lies at the intersection of three twofold axes (Wyckoff position 8b). It is coordinated by four N atoms of the pyridine rings, as well as by two N atoms of N-nitrite groups. The last two N atoms are located on a twofold axis (Wyckoff position 16f). The O atoms of the water molecules are situated on a twofold axis (Wyckoff position 16e). Short intermolecular contacts are observed in the crystal structure, viz. N-O···OW and N-O···H-OW contacts between nitrite and water, and weak C-H···OW hydrogen bonds between pyridine and water. Thus, the intercalated water molecules act as bridges connecting the trans-[Ru(NO(2))(2)(py)(4)] molecules into a three-dimensional network.