Thermodynamics of formation of solid solutions between BaZrO3 and BaPrO3
| Autor: | Vladimir V. Sereda, Anton L. Sednev-Lugovets, Andrey Yu. Zuev, Dmitry S. Tsvetkov, I.L. Ivanov, Dmitry Malyshkin |
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| Přispěvatelé: | Russian Science Foundation (project No. 18-73-00022) |
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Materials science
Standard molar entropy THERMODYNAMIC PROPERTIES PREDICTION General Chemical Engineering chemistry.chemical_element symbols.namesake thermodynamics Goldschmidt tolerance factor THERMODYNAMICS Materials Chemistry QD1-999 Perovskite (structure) thermodynamic properties prediction Barium General Chemistry DOPED BARIUM ZIRCONATE Enthalpy of mixing Standard enthalpy of formation Gibbs free energy Crystallography Chemistry doped barium zirconate chemistry symbols Solid solution |
| Zdroj: | Chimica Techno Acta; Том 7, № 2 (2020); 42-50 Chimica Techno Acta, Vol 7, Iss 2, Pp 42-50 (2020) |
| ISSN: | 2411-1414 |
| Popis: | A linear relationship between the standard enthalpy of formation from binary oxides, Δ f H ox , and the Goldschmidt tolerance factor, t , for some A II B IV O 3 (A = Ca, Sr, Ba; B = Ti, Zr, Hf, Ce, Pr, Tb, U, Pu, Am) perovskite oxides was used for estimation of Δ f H ox of Pr-substituted barium zirconates BaZr 1– x Pr x O 3 . A dependence of the relative change of the standard entropies, S 298 , on the relative change of the molar volumes in the reactions of formation of A II B IV O 3 (A = Ca, Sr, Ba; B = Ti, Zr, Hf, Ce) from binary oxides was also found to be linear. Using this dependence, a relatively precise method of estimating S 298 was proposed, and S 298 of BaPrO 3 was calculated as (162.8 ± 2.8) J·mol -1 ·K -1 . Knowing S 298 of BaPrO 3 and using the literature data for S 298 of BaZrO 3 , the values of S 298 of BaZr 1– x Pr x O 3 were predicted on the assumption that BaZr 1– x Pr x O 3 is a regular or ideal solution of BaPrO 3 in BaZrO 3 as evidenced by the very small enthalpy of mixing calculated based on the estimated Δ f H ox . The values of standard entropy changes, Δ f S ox , and Gibbs energy changes, Δ f G ox , for the reactions of formation of BaZr 1– x Pr x O 3 from BaO, ZrO 2 and PrO 2 were also estimated. Substituting Pr for Zr in BaZr 1– x Pr x O 3 results in Δ f H ox and Δ f G ox becoming more positive, indicating the decrease of the relative stability with respect to the corresponding binary oxides. Expanded uncertainties of the estimated values of Δ f H ox and Δ f G ox are equal to 14 kJ∙mol -1 , and those of S 298 and Δ f S ox – less than 2.8 J∙mol -1 ·K -1 and 3.5 J∙mol -1 ·K -1 , respectively, for BaZr 1– x Pr x O 3 ( x = 0.0–1.0). |
| Databáze: | OpenAIRE |
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