Bis(acetyl­acetonato-κ²O,O′)bis­(pyridine-κN)nickel(II) dihydrate

The title compound, [Ni(C₅H₇O₂)₂(C₅H₅N)₂]·2H₂O, crystallizes with two half-mol­ecules in the asymmetric unit. The Ni^II ion of each unique complex mol­ecule lies on an inversion centre and has an octa­hedral coordination geometry. The crystal structure features weak O—H...O hydrogen bonds, which form chains running parallel to the a axis.

Poly[[diaqua­bis­(μ₂-4,4′-bipyrid­yl)cobalt(II)] dinitrate tetra­hydrate]

The title compound, {[Co(C₁₀H₈N₂)₂(H₂O)₂](NO₃)₂·4H₂O}_n, (C₁₀H₈N₂ = 4,4′-bipyridine = 4,4′-bpy) is a layered coordination polymer built up from a cationic square grid extending in (101) enclosing uncoordinating nitrate ions and water mol­ecules. The Co^II ion has site symmetry 2 and one of the 4,4′-bpy ligands is generated by twofold symmetry [two N atoms and two C atoms lie on the rotation axis and the dihedral angle between the pyridine rings is 45.66 (5)°]. The other 4,4′-bpy ligand is generated by a crystallographic inversion center. The Co^II ion exhibits a slightly distorted octa­hedral coordination geometry defined by two O atoms of two coordinating water mol­ecules and four N atoms from four bridging 4,4′-bpy ligands. The structure is consolidated by O—H...O, C—H...O and C—H...N hydrogen bonds.