Determination of the thermodynamic stability of europium boride (EuB6)

• Published in: Journal of thermal analysis and calorimetry 2018-04, Vol.132 (1), p.275-283
• Main Authors: Jain, Ashish, Kandan, R.
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Chemistry; Chemistry and Materials Science; Electrolytic cells; Energy measurement; Enthalpy; Europium; Europium compounds; Free energy; Heat of formation; Inorganic Chemistry; Measurement Science and Instrumentation; Physical Chemistry; Polymer Sciences; Rare earth metal compounds; Solid electrolytes; Specific heat; Thermodynamics; Yttria-stabilized zirconia; Yttrium oxide; Zirconium dioxide
• ISSN: 1388-6150; 1588-2926
• DOI: 10.1007/s10973-017-6876-1

The standard Gibbs energy of formation of europium boride ( Δ f G ∘ EuB 6 ) was experimentally measured by the electromotive force method by using yttria-stabilized zirconia (YSZ) as the solid electrolyte. Two galvanic cells, viz., cell I: Pt, EuB 6 (s), Eu 2 O 3 (s), B (s) | YSZ | NiO (s), Ni (s), Pt and cell II: Pt, EuB 6 (s), Eu 2 O 3 (s), B (s) | YSZ | FeO (s), Fe (s), Pt, were constructed in order to determine the Δ f G ∘ of EuB 6 (s). Enthalpy increments on EuB 6 (s) were measured by using inverse drop calorimeter over the temperature range 765–1549 K. The heat capacity, entropy and the Gibbs energy functions were derived from these experimental data in the temperature range 300–1600 K. The mean value of the standard enthalpy of formation of EuB 6 ( Δ f H 298 ∘ EuB 6 ) was obtained by Δ f G ∘ values and the Gibbs energy functions (fefs) of EuB 6 (s) derived from drop calorimetric data. The mean values of Δ f H 298 ∘ E u B 6 derived from the Δ f G ∘ data obtained from cells I and II were − 173 ± 3 and − 180 ± 3 kJ mol −1 , respectively. These values were found to be in good agreement with the values calculated from the reported data on enthalpy increments.