Kopan A. Thermodynamic properties of rare-earth selenides of cerium subgroup and gadolinium.

Heat capacity of La3Se4, Pr2Se3, Pr3Se4, Nd3Se4, Sm2Se3, Gd2Se3 was measured for the first time in the temperatures range from 5(50) to 300 K by the adiabatic calorimetry method. The temperature dependences of enthalpy for LaSe, La2Se3, La3Se4, Pr2Se3, Pr3Se4, Nd2Se3, Nd3Se4, Sm2Se3, Gd2Se3 selenides were obtained by the mixture method for the first time over the range 300 - 2300 К. The melting points of all investigated selenides were determined, and enthalpies and entropies of melting were calculated for the first time. Method of estimation of thermodynamic functions of REM selenides was proposed. The temperature dependences of principal thermodynamic functions of CeSe, PrSe, NdSe, Ce3Se4, Pm3Se4, Sm3Se4, Eu3Se4, Ce2Se3, Pm2Se3, Eu2Se3 were defined over the range 300 - 1800 К.