Second-sphere coordination in anion binding: trans-bis­(ethyl­enediamine-κ²N,N′)dinitro­cobalt(III) periodate

In the title complex, [Co(NH₂CH₂CH₂NH₂)₂(NO₂)₂](IO₄), the cations are situated on two sets of inversion centres and are linked by pairs of complementary N—H...O hydrogen bonds into columns arranged in an approximately hexa­gonal manner. The periodate anions can be envisaged as occupying triangular hollows above and below approximate hexa­gonal close-packed layers of trans-bis­(ethyl­enediamine-κ²N,N′)dinitro­cobalt(III) cations.