Comparison of the hydrogen-bond patterns in 2-amino-1,3,4-thia­diazol­ium hydrogen oxalate, 2-amino-1,3,4-thia­diazole–succinic acid (1/2), 2-amino-1,3,4-thia­diazole–glutaric acid (1/1) and 2-amino-1,3,4-thia­diazole–adipic acid (1/1)

In 2-amino-1,3,4-thiadiazolium hydrogen oxalate, 2-amino-1,3,4-thiadiazole–glutaric acid (1/1) and 2-amino-1,3,4-thiadiazole–adipic acid (1/1), the graph-set motifs (8), with N—H...O and O—H...N hydrogen bonds of moderate strength, are the most prominent features (N—H...O hydrogen bonds are present only in 2-amino-1,3,4-thiadiazolium hydrogen oxalate). The hydrogen-bond pattern of 2-amino-1,3,4-thiadiazole–succinic acid (1/2) differs considerably from the other title structures, though N—H...O and O—H...N hydrogen bonds of moderate strength are also present. There are nonbonding S...O interactions in all four structures, however, the packing patterns are quite different.