Low-temperature heat capacity and thermodynamic functions of KTh2(PO4)3

•Temperature dependence of heat capacity of KTh2(PO4)3 has been measured by precision adiabatic vacuum calorimetry.•The thermodynamic functions of the KTh2(PO4)3 have been determined for the range from T → 0 to 350 K.•The character of heterodynamics of structure was detected.•The high-temperature X-ray diffraction method was used for the determination of thermal expansion coefficients.

In the present work temperature dependence of heat capacity of KTh2(PO4)3 has been measured for the first time in the range from 5.5 to 350 K by precision adiabatic vacuum calorimetry. The experimental data were used to calculate standard thermodynamic functions, namely the heat capacity Cp°(T), enthalpy H°(T) − H°(0), entropy S°(T) − S°(0) and Gibbs function G°(T) − H°(0), for the range from T → 0 to 350 K. The value of the fractal dimension D in the function of multifractal generalization of Debye's theory of the heat capacity of solids was estimated and the character of heterodynamics of structure was detected. The high-temperature X-ray diffraction method was used for the determination of thermal expansion coefficients.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide