Crystal structure of 1-butyl-3-{2-[(indan-5-yl)amino]-2-oxoeth-yl}-1-imidazol-3-ium chloride.

In the cation of the title mol-ecular salt, CHNO·Cl, an intra-molecular C-H⋯O hydrogen bond stabilizes the almost coplanar orientation of the aromatic ring of the indane unit and the amide plane. In the crystal, the packing is dominated by inter-molecular C-H⋯Cl hydrogen-bonding inter-actions that result in the formation of slab-like structures propagating along [010]. The slabs are linked by weak C-H⋯O inter-actions, forming layers lying parallel to (100). The methyl-ene carbon atom of the indanyl substituent is disordered over two positions with a refined occupancy ratio of 0.84 (2):0.16 (2). The crystal studied was refined as a twin with matrix [1 0 0.9, 0 0, 0 0 ]; the resulting BASF value is 0.30.