Redetermination of cis-bis­(ethyl­ene­diamine-κ²N,N′)bis­(nitrito-κN)cobalt(III) (ethyl­enediamine-κ²N,N′)tetra­kis­(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 inter­ionic and inter­molecular inter­actions. The crystal structure consists of an octa­hedrally coordinated cationic Co^III complex ion, an octa­hedrally coordinated anionic Co^III complex ion and a lattice water mol­ecule. The complex cation, complex anion and lattice water mol­ecule are connected by an intricate network of O—H...O and N—H...O hydrogen bonds, forming a three-dimensional structure.