Electrochemical Determination of Gibbs Energy of Formation of LaCrO3 Using a Composition-Graded Bielectrolyte

Jacob, Kallarackel Thomas and Gupta, Sapna and Singh, Prabhakar (2013) Electrochemical Determination of Gibbs Energy of Formation of LaCrO3 Using a Composition-Graded Bielectrolyte. In: JOURNAL OF THE AMERICAN CERAMIC SOCIETY, 96 (10). pp. 3272-3278.

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Abstract

Presented are new measurements of the standard Gibbs free energy of formation of rhombohedral LaCrO3 from component oxides La2O3 and Cr2O3 in the temperature range from 875 to 1175K, using a bielectrolyte solid-state cell incorporating single crystal CaF2 and composition-graded solid electrolyte (LaF3)(y)(CaF2)(1-y) (y=0-0.32). The results can be represented analytically as Delta G(f(ox))(o) (+/- 2270)/Jmol(-1)=-72329+4.932 (T/K). The measurements were undertaken to resolve serious discrepancies in the data reported in the literature. A critical analysis of previous electrochemical measurements indicates several deficiencies that have been rectified in this study. The enthalpy of formation obtained in this study is consistent with calorimetric data. The standard enthalpy of formation of orthorhombic LaCrO3 from elements at 298.15K computed from the results of this study is Delta H-f(298.15)(o)/kJmol(-1)=-1536.2 (+/- 7). The standard entropy of orthorhombic LaCrO3 at 298.15K is estimated as 99.0 (+/- 4.5)J(molK)(-1).

Item Type:	Journal Article
Publication:	JOURNAL OF THE AMERICAN CERAMIC SOCIETY
Publisher:	WILEY-BLACKWELL
Additional Information:	Copyright for this article belongs to the WILEY-BLACKWELL,NJ USA
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	31 Jan 2014 11:49
Last Modified:	31 Jan 2014 11:49
URI:	http://eprints.iisc.ac.in/id/eprint/48279

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