Ching Kheng, C.K.Fun, H.-K.Isloor, A.M.Isloor, N.2026-02-052010Acta Crystallographica Section E: Structure Reports Online, 2010, 66, 9, pp. o2250-o225116005368https://doi.org/10.1107/S1600536810030941https://idr.nitk.ac.in/handle/123456789/27419The asymmetric unit of the title compound, 2C<inf>5</inf>H <inf>7</inf>N<inf>2</inf> +·SO<inf>4</inf> 2-·H<inf>2</inf>O, contains two 4-aminopyridinium cations (A and B), a sulfate dianion and a water molecule. One of the 4-aminopyridinium cations (B) is disordered over two orientations with refined site occupancies of 0.568 (4) and 0.432 (4). The non-H atoms of the 4-aminopyridinium cations are essentially coplanar, with a maximum deviation of 0.055 (1) Å (in cation A), 0.022 (3) Å (for the major component in cation B) and 0.009 (3) Å (for the minor component in cation B). In the crystal, the sulfate O atoms link the 4-aminopyridinium cations and water molecules into a three-dimensional network via intermolecular O-H?O, N-H?O and C-H?O hydrogen bonds. The crystal structure is further consolidated by N-H?O(water) and C-H?O(water) hydrogen bonds.