Hexakis(imidazole-N3)nickel(II) carbonate pentahydrate

The crystal structure of the title complex, [Ni(C3H4-N2)6]CO3.5H 2O, which is isostructural with the Cd, Co and Ru analogues, is built up from cationic and anionic sheets parallel to the basal plane of the hexagonal unit cell. The former contain the [Ni(C3H4N2)6]2+ cations and the latter the CO3 2- anions together with the hydration water molecules. These are disordered on both sides of the P63/m mirror plane, which thus exists in an average sense only. The sheets are linked by an extensive hydrogen-bonding system involving the non-coordinated NH imidazole groups, the hydration water molecules and the O atoms of the carbonate anions. The latter are acceptors of nine simultaneous strong hydrogen bonds