Redetermination of cis-bis-(ethyl-ene-diamine-κ(2) N,N')bis-(nitrito-κN)cobalt(III) (ethyl-enediamine-κ(2) N,N')tetra-kis-(nitrito-κN)cobaltate(III) monohydrate.

The structure of the title compound, [Co(NO2)2(NH2CH2CH2NH2)2][Co(NO2)4(NH2CH2CH2NH2)]·H2O, was redetermined with a modern CCD-equipped diffractometer. In comparison with the original determination based on photographic data [Kushi et al. (1976 ▶). Inorg. Nucl. Chem. Lett. 12, 629-633], the current study allows the location of reliable postions for the H atoms and thus leads to better understanding of the inter-ionic and inter-molecular inter-actions. The crystal structure consists of an octa-hedrally coordinated cationic Co(III) complex ion, an octa-hedrally coordinated anionic Co(III) complex ion and a lattice water mol-ecule. The complex cation, complex anion and lattice water mol-ecule are connected by an intricate network of O-H⋯O and N-H⋯O hydrogen bonds, forming a three-dimensional structure.