Diammonium 1,1′,3,3′-tetramethyl-2,2′,4,4′,6,6′-hexaoxoperhydro-5,5′-bipyrimidine-5,5′-diide monohydrate

In the title hydrated salt, 2NH(4)(+)center dot C(12)H(12)N(4)O(6)(2-)center dot H(2)O, the two hexahydropyrimidine rings in the dianion are inclined to one another at a dihedral angle of 62.76 (5)degrees. In the crystal structure, the anions and water molecules are linked into sheets parallel to the bc plane by intermolecular O-H center dot center dot center dot O hydrogen bonds and sustained by C-H center dot center dot center dot O contacts. The linking of the anions and water molecules with the cations by N-H center dot center dot center dot O hydrogen bonds creates a three-dimensional extended network. The crystal structure is further stabilized by very weak C-H center dot center dot center dot pi interactions.