The crystal structure of butenafine hydrochloride has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional theory techniques. Butenafine hydrochloride crystallizes in space group P21 (#4) with a = 13.94807(5), b = 9.10722(2), c = 16.46676(6) Å, β = 93.9663(5)°, V = 2086.733(8) Å3, and Z = 4. Butenafine hydrochloride occurs as a racemic co-crystal of R and S enantiomers of the cation. The crystal structure is characterized by parallel stacks of aromatic rings along the b-axis. Each cation forms a strong discrete N–H⋯Cl hydrogen bond. The chloride anions also act as acceptors in several C–H⋯Cl hydrogen bonds from methylene, methyl, and aromatic groups. The powder pattern has been submitted to ICDD for inclusion in the Powder Diffraction File™ (PDF®).
