Structure determination and Hirshfeld surface analysis of new cocrystal and salt forms of 5-aminotetrazole with hydroxy- and nitro-substituted carboxylic acids

Two new crystalline solids, namely, 5-amino­tetra­zole–3,5-di­hydroxy­benzoic acid–water (1/4/6), CH₃N₅·4C₇H₆O₄·6H₂O (I), and 5-amino­tetra­zolium 3,5-di­nitro­salicylate, CH₄N₅⁺·C₇H₃N₂O₇− (II), have been synthesized and characterized by single-crystal X-ray diffraction and Hirshfeld surface analysis. The crystal packing arrangements of I and II are governed by N—H⋯O and O—H⋯O hydrogen-bonding inter­actions. In cocrystal I, adjacent acid mol­ecules are linked through O—H⋯O hydrogen bonds, forming a dimer with an R₂²(8) motif. In salt II, the tetra­zolium cation and acid anion are linked through N—H⋯O hydrogen bonds to also form a dimer with an R₂²(8) motif. Further N—H⋯O and O—H⋯O hydrogen bonds help to stabilize the crystal packing, along with aromatic π–π stacking inter­actions in I and carbon­yl⋯π inter­actions in II. The Hirshfeld surface analysis and fingerprint plots reveal that O⋯H/H⋯O inter­actions contribute 34.4% of the total inter­actions in the crystal packing of cocrystal I and 36.7% in salt II.