High-temperature calorimetric measurements on RE2TeO6 (RE = Gd, Er)

The ternary compounds of Gd 2 TeO 6 (s) and Er 2 TeO 6 (s) were prepared by solid-state route and characterized by XRD, ICP-AES and ICP-MS techniques. Enthalpy measurements were taken on these compounds by inverse drop calorimetric method by using a high-temperature differential calorimeter over the...

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Veröffentlicht in:Journal of thermal analysis and calorimetry 2020-11, Vol.142 (3), p.1261-1274
Hauptverfasser: Kandan, R., Jain, Ashish, Venkatesh, P., Prabhakara Reddy, Bandi
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Sprache:eng
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Zusammenfassung:The ternary compounds of Gd 2 TeO 6 (s) and Er 2 TeO 6 (s) were prepared by solid-state route and characterized by XRD, ICP-AES and ICP-MS techniques. Enthalpy measurements were taken on these compounds by inverse drop calorimetric method by using a high-temperature differential calorimeter over the temperature region 669–1272 K. The measured enthalpy increment values of these compounds were fitted to four term nonlinear polynomial functions in temperature using least-squares method. With the fitted equations, other thermodynamic function such as heat capacity, entropy and free energy functions have been computed in the temperature range 298–1300 K. The derived free energy functions of RE 2 TeO 6 (RE = Gd, Er), from enthalpy increments measurements were combined with the standard Gibbs energies of formation of RE 2 TeO 6 (RE = Gd, Er), derived from vapor pressure measurement, to obtain Δ f H 298 o of Gd 2 TeO 6 (s) and Er 2 TeO 6 (s).
ISSN:1388-6150
1588-2926
DOI:10.1007/s10973-020-09567-1