The heat capacity of RTez (R = Pr, La; z = 1.33, 1.37, 1.47, and 1.50) has been measured in a vacuum adiabatic calorimeter over the temperature range 5 to 273 °K. The heat capacity contribution due to the Schottky effect has been determined. The energy level set (ϵi) of the 3H4 state of the Pr3+ ion split by the crystal field with Th3P4 symmetry is calculated using the method of Stevens equivalent operators in the point charge model. For Pr3Te4 ϵi = 0,27.5, 88.2 (a doublet), 113.5, 331.7, 338.3 (a doublet), 345.5 is found. The dependence of the first split levels on composition is examined. From the investigation of the entropy due to the Schottky effect, the conclusion is made that no transition except the Schottky anomaly does exist in the Pr3Te4–Pr2Te3 system in the temperature range 5 to 273 °K.

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The influence of the crystal‐to‐glass transition on the local structure in semiconducting compounds and alloys such as As2S3, As2Se3, As2Te3, AsSI, AsSeI, As4Te5I2, As2Se3 · As2Te3, Ge15Te85, and As4Ge15Te81 is analysed by Mössbauer spectroscopy for nuclei of 125Te, 127I, 129Te(129I), and 119Sn and by measuring the chemical shift of the AsLα1 line. It is shown that for such compounds and alloys as As2Te3, As4Te5I2, Ge15Te85, As4Ge15Te81 the transition into the glassy state may take place only under conditions of severe quenching. For such semiconductors the crystal‐to‐glass transition is accompanied by a change in the symmetry of the local environment of the tellurium, iodine, and germanium atoms. A correlation between the change in the electric conductivity and density and the change in the local structure at the crystal‐to‐glass transition is observed.

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