Commercial azelastine hydrochloride crystallizes in the monoclinic space group P21/n (#14) with a = 13.7844(5), b = 16.39920(14), c = 9.41231(22) Å, β = 97.5340(20)°, V = 2109.32(4) Å3, and Z = 4. The lattice parameters differ by −0.02, +0.04, and +0.04% from those in the previous determination (reflecting differences in the temperature and the sample source), and are more precise, from the use of synchrotron radiation. The experimental powder pattern is included in the Powder Diffraction File™ (PDF®) as entry 00-070-1219.
