Crystal structure of 2-methyl-1-imidazol-3-ium 3,5-di-carb-oxy-benzoate.

The structure of the title salt, CHN ·CHO (), is reported. The compound is built from a protonated 2-methyl-imidazole and a singly deprotonated trimesic acid. Detailed analysis of bond distances and angles for both ions reveals subtle differences compared with their neutral mol-ecule counterpart.