Comprehensive thermodynamic and structural study of hevein

Abstract In the present work the temperature dependence of heat capacity for hevein has been measured for the first time over the temperature range from 5 K to 344 K using by precision adiabatic vacuum calorimetry. Based on the experimental data, the thermodynamic functions of the hevein, namely, the heat capacity, enthalpy H° ( T ) −  H °(0), entropy S° ( T ) −  S° (0) and Gibbs function G° ( T ) −  H °(0) have been evaluated from the experimental values for the range from T  → 0 K to 344 K. The low-temperature X-ray diffraction was used for the determination of type phase transition at 222.8 K and coefficients of thermal expansion.