Crystal structure and Hirshfeld surface analysis of 1,2,4-triazolium hydrogen oxalate

The asymmetric unit of the title 1:1 salt 1,2,4-triazolium hydrogen oxalate, C2H4N3 + C2HO4 (I), comprises one 1,2,4-triazolium cation and one hydrogen oxalate anion. In the crystal, the hydrogen oxalate anions are linked by O— HO hydrogen bonds into chains running parallel to [100]. In turn, the anionic chains are linked through the 1,2,4-triazolium cations by charge-assisted + N— HO hydrogen bonds into sheets aligned parallel to (011). The sheets are further stacked through – interactions between the 1,2,4-triazolium rings [centroid-to-centroid distance = 3.642 (3) A˚ , normal distance = 3.225 (3) A˚ , slippage 1.691 A˚ ], resulting in the formation of a three-dimensional supramolecular network. Hirshfeld surface analysis of the title salt suggests that the most significant contributions to the crystal packing are by HO/OH and HN/NH contacts involving the hydrogen bonds.