Thermodynamic properties of scandium, lanthanum, neodymium and gadolinium silicides and germanides

Thermodynamic modeling of the gadolinium–germanium system

“…The results somewhat differ from the data obtained by the emf method in Refs. [25,26], but agree well with the direct calorimetric measurement of Meschel and Kleppa [27]. The dissolution experiments had been repeated using different solvents (Al, Cu and Sn) and the reliability of the obtained results was confirmed [28].…”

“…From it, the enthalpy of formation of Gd 3 Ge 5 can be derived to be about −80.21 kJ/mol-atoms. The same group afterwards determined the Gibbs free energy, enthalpy and entropy of formation of the stable compounds also by the emf method [26]. The enthalpies of formation (kJ/mol-atoms) were reported to be −82.9 ± 3.4 for Gd 3 Ge 5 , −87.7 ± 3.6 for Gd 2 Ge 3 , −105.4 ± 5.0 for GdGe, −115.3 ± 5.5 for Gd 5 Ge 4 and −112.8 ± 7.0 for Gd 5 Ge 3 .…”

Experimental investigation and thermodynamic modeling of the Gd–Si system

“…However, as shown in Figs. 11 and 12, there are large discrepancies between the calculation and experimental data [16,18,19] for the enthalpy and entropy of formation of solids at 800 K, especially on the Gd-rich side. The calculated enthalpies of mixing of the liquid phase at 1770 K together with the experimental data of Kanibolotsky et al [22,24] and Beloborodova et al [23] are shown in Fig.…”

“…The enthalpy of formation for Gd 5 Si 3 [13,14], Gd 5 Si 4 [13], GdSi [13,15], Gd 2 Si 3 [13] and GdSi 2−x [13,14] were investigated by Usenko et al [13] by solution drop calorimetry, and Meschel and Kleppa [14,15] by direct-synthesis calorimetry. The Gibbs energy, enthalpy and entropy of formation of the compounds Gd 5 Si 3 [16,17], Gd 5 Si 4 [16,17], GdSi [16], Gd 2 Si 3 [16] and GdSi 2−x [16,18] were investigated by Lukashenko et al [16,18], Sidorko and Polotsokaya, [17] and Lukashenko and Polotskaya [19] by measuring the emf of high-temperature galvanic cells in the temperature range of 600-960 K and the Gibbs energy of formation of Gd 3 Si 5 was calculated by Uspenskaya et al [20]. The enthalpies of mixing of Gd-Si alloys have been measured by high-temperature calorimetry on Si-rich side (94-100 at.% Si) at 1800 K [21], in the composition ranges 0 < x Si < 0.2 and 0.8 < x Si < 1, and 0 < x Si < 0.2 and 0.7 < x Si < 1 at 1760 K [22,23], and those over the entire composition range at 1770 ± 5 K [24].…”

Thermodynamic modeling of the Ge-La binary system

“…Some evaluations on the enthalpies, entropies, and Gibbs energies of the compounds in the system were given in Refs. [30][31][32][33][34] as listed in Table 2.…”