A long symmetric N⋯H⋯N hydrogen bond in bis-(4-amino-pyridinium)(1+) azide(1-): redetermination from the original data.

The structure of the title mol-ecular salt, CHN·N, has been redetermined from the data published by Qian & Huang [ (2010), E, o3086; refcode WACMIY (Groom , 2016)]. The improvement of the present redetermination consists in a correction of the site-occupancy parameter of the bridging H atom between the pyridine rings, as well as of its position. The present study has shown that the bridging H atom (site symmetry 2) is involved in a symmetric N⋯H⋯N hydrogen bond, which is one of the longest ever observed [N⋯N = 2.678 (3) Å]. In addition, there are also present weaker N-H⋯N hydrogen bonds (am = amine and az = azide) of moderate strength and π-electron pyridine⋯π-electron inter-actions in the structure. All the azide N atoms also lie on a twofold axis.