Abstract:

The crystal structure of ephedrine hydrochloride was determined by means of X-ray crystallography. The crystal system of the compound is monoclinic, and the space group is P2₁. Unit cell parameters are a=0.7308(6) nm, b=0.6124(5) nm, and c=1.2618(11) nm; α=90°, β=102°, and γ=90°; Z=2. Low-temperature heat capacities of the title compound were measured with an improved precision automated adiabatic calorimeter over a temperature range from 77 K to 396 K. A polynomial equation of the heat capacities as a function of temperature in the temperature region was fitted by the least-squares. Based on the fitted polynomial equation, the smoothed heat capacities and thermodynamic functions of the compound relative to the standard reference temperature 298.15 K were calculated and tabulated at the intervals of 5 K.

Key words: Ephedrine hydrochloride C10H16NOCl(s); X-ray crystallography; Adiabatic calorimetry; Low-temperature heat capacity; Thermodynamic function