High-resolution crystal structure of the double nitrate hydrate [La(NO)][Ni(HO)]·6HO.

This study introduces bis-[hexa-kis-(nitrato-κ ,')lanthanum(III)] tris-[hexa-aqua-nickel(II)] hexa-hydrate, [La(NO)][Ni(HO)]·6HO, with a structure refined in the hexa-gonal space group . The salt com-prises [La(NO)] icosa-hedra and [Ni(HO)] octa-hedra, thus forming an intricate network of inter-penetrating honeycomb lattices arranged in layers. This arrangement is stabilized through strong hydrogen bonds. Two successive layers are connected the second [Ni(HO)] octa-hedra, forming sheets which are stacked perpendicular to the axis and held in the crystal by van der Waals forces. The synthesis of [La(NO)][Ni(HO)]·6HO involves dissolving lanthanum(III) and nickel(II) oxides in nitric acid, followed by slow evaporation, yielding green hexa-gonal plate-like crystals.