Bis(2,3-diamino-pyridinium) succinate trihydrate.

In the title salt, 2C(5)H(8)N(3) (+)·C(4)H(4)O(4) (2-)·3H(2)O, the asymmetric unit contains a protonated 2,3-diamino-pyridinium cation, half of a succinate dianion (disposed about a centre of inversion), and one and a half water mol-ecules. One of the water mol-ecules is disordered over two sites with occupancies of 0.670 (17) and 0.330 (17). The other water mol-ecule has an occupancy of 0.5 (from refinement). The pyridine N atom of the 2,3-diamino-pyridine mol-ecule is protonated. The protonated N atom and one of the 2-amino H atoms are hydrogen bonded to the succinate anion through a pair of N-H⋯O hydrogen bonds, forming an R(2) (2)(8) ring motif. In the crystal, mol-ecules are consolidated into a three-dimensional network by N-H⋯O and O-H⋯O inter-actions.