Putrescinium dichloride: a redetermination at 100 K

The crystal structure of the title compound, C4H14N22+·2Cl−, has been redetermined at 100 (1) K. In the room-temperature structure [Chandrasekhar & Pattabhi (1980). Acta Cryst. B36, 2486–2488], the H atoms were located but their parameters were not refined. Since the hydrogen bonds in this structure are extensive, the H-atom positions are of primary importance. The dication lies on a centre of symmetry and the N atoms are slightly displaced [0.019 (4) A] from the plane of the four C atoms. N—H⋯Cl and C—H⋯Cl hydrogen bonds form a three-dimensional network.