The pseudosymmetric structure of bis-(pentane-1,5-diaminium) iodide tris-(triiodide).

The asymmetric unit of the title compound, [H(3)N(CH(2))(5)NH(3)](2)I[I(3)](3) or 2C(5)H(16)N(2) (2+)·3I(3) (-)·I(-), consists of two crystallographically independent pentane-1,5-diaminium dications and two triiodide anions in general positions besides two additional triiodide and two iodide anions located on twofold axes. The compound crystallizes in the centrosymmetric monoclinic space group P2/n. The structure refinement was handicapped by the pseudosymmetry (pseudo-centering) of the structure and by twinning. The crystal structure is composed of two alternate layers, which differ in their arrangement of the pentane-1,5-diaminium dications and the iodide/triiodide anions and which are connected via weak to medium-strong N-H⋯I hydrogen bonds, constructing a complex hydrogen-bonded network.