Abstract
In the title salt, C2H5N4+center dot C2HO4-, the hydrogen oxalate anions form corrugated chains parallel to the c axis, linked by intermolecular O-H center dot center dot center dot O hydrogen bonds. The 5-amino-1H1,2,4-triazol-4- ium cations are connected into centrosymmetric clusters via weak C-H center dot center dot center dot N hydrogen bonds forming nine-membered rings with an R33 (9) motif. These clusters are interconnected via anions through N-H center dot center dot center dot O hydrogen bonds, building a three-dimensional network.