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organic compounds
The asymmetric unit of the crystal consists of one sulfate ion, one water molecule and two 2,4-diaminopyrimidine (DAP) molecules stacked parallel to the b direction with average perpendicular seperations of 3.310 (4) and 3.343 (4) Å, respectively. The tilt angle between the least squares planes of the two DAP molecules in the asymmetric unit is 2.1 (1)°. The structure is stabilized by stacking forces, N-HN hydrogen bonds and N-HO hydrogen bonds.