Abstract
The title hydrated mol-ecular salt, C19H15N4 +·Cl-·2.5H2O, has two tri-phenyl-tetra-zolium cations, two chloride anions and five water mol-ecules in the asymmetric unit. The cations differ in the conformations of the phenyl rings with respect to the heterocyclic core, most notably for the C-bonded phenyl ring, for which the N-C-C-C torsion angles differ by 36.4 (3)°. This is likely a result of one cation accepting an O-H⋯N hydrogen bond from a water mol-ecule [O⋯N = 3.1605 (15) Å], while the other cation accepts no hydrogen bonds. In the extended structure, the water mol-ecules are involved in centrosymmetric (H2O)2Cl2 rings as well as (H2O)4 chains. An unusual O-H⋯π inter-action and weak C-H⋯O and C-H⋯Cl hydrogen bonds are also observed.