The crystal structure of protriptyline hydrochloride has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional theory techniques. Protriptyline hydrochloride crystallizes in space group P21/n (#14) with a = 10.10772(19), b = 32.0908(6), c = 10.45302(21) Å, β = 92.8748(10)°, V = 3,386.33(15) Å3, and Z = 8 at 298 K. The crystal structure contains the expected N–H···Cl hydrogen bonds, which link the cations and anions into crankshaft-shaped chains along the c-axis. The cations and the anions form layers parallel to the ac-plane, with van der Waals interactions between the layers. The powder pattern has been submitted to the International Centre for Diffraction Data (ICDD®) for inclusion in the Powder Diffraction File™ (PDF®).
