Bis(melaminium) succinate succinic acid monosolvate dihydrate.

The asymmetric unit of the solvated title salt, 2C(3)H(7)N(6) (+)·C(4)H(4)O(4) (2-)·C(4)H(6)O(4)·2H(2)O, contains one essentially planar melaminium (2,4,6-triamino-1,3,5-triazin-1-ium) cation (r.m.s. deviation of the non-H atoms = 0.0097 Å), one-half of a succinate anion, one-half of a succinic acid solvent mol-ecule and one water molecule of crystallization; full mol-ecules are generated by inversion symmetry. Supra-molecular layers parallel to (12-1) are formed through extensive inter-molecular hydrogen bonding of the types O-H⋯O, N-H⋯N and N-H⋯O between the components.