Synthesis and crystal structure of 1<i>H</i>-1,2,4-triazole-3,5-diamine monohydrate

The title compound, a hydrate of 3,5-di-amino-1,2,4-triazole (DATA), C₂H₅N₅·H₂O, was synthesized in the presence of sodium perchlorate. The evaporation of H₂O from its aqueous solution resulted in anhydrous DATA, suggesting that sodium perchlorate was required to precipitate the DATA hydrate. The DATA hydrate crystallizes in the <i>P</i>2₁/<i>c</i> space group in the form of needle-shaped crystals with one DATA and one water mol-ecule in the asymmetric unit. The water mol-ecules form a three-dimensional network in the crystal structure. Hirshfeld surface analysis revealed that 8.5% of the inter-molecular inter-actions originate from H⋯O contacts derived from the incorporation of the water mol-ecules.