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

The structure of the title salt, C 4 H 7 N 2 + ·C 9 H 5 O 6 - ( 1 ), 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. Analysis of the crystal packing in compound 1 reveals the formation of undulating chains by the ions through hydrogen bonding. The chains stack along the b axis through π-π inter-actions and inter-connect with other chains in an out-of-phase arrangement along the ac plane through further hydrogen-bonding inter-actions.