Thermodynamic studies of CaLaFe₁₁O₁₉(s)
- Bhabha Atomic Research Centre, Trombay, Product Development Division, Mumbai 400085 (India)
- Peter A. Rock Thermochemistry Laboratory and NEAT ORU, University of California Davis, Davis, CA 95616 (United States)
Thermodynamic studies on CaLaFe₁₁O₁₉(s) were carried out using Knudsen effusion mass spectrometry and calorimetry, viz. differential scanning calorimetry and high temperature oxide melt solution calorimetry. Standard molar Gibbs free energy of formation (Δ{sub f}G⁰{sub m}), enthalpy of formation and heat capacity (C⁰{sub ₚ,m}) of the compound were calculated as a function of temperature for the first time. C⁰{sub ₚ,m}(CaLaFe₁₁O₁₉) was determined and used for second law analysis, from which enthalpy and entropy of formation of the compound were calculated and the respective values are: Δ{sub f}H⁰{sub m}(298.15 K)/kJ mol⁻¹=-6057(±8) and S⁰{sub m}(298.15 K)/J K⁻¹ mol⁻¹=427(±5). Δ{sub f}H⁰{sub m}(298.15 K)/kJ mol⁻¹: -6055(±6) was also calculated using oxide melt solution calorimetry, which is in close agreement with the second law value. A heat capacity anomaly was also observed at T=684 K. A table of thermodynamic data from 298.15 K to 1000 K for CaLaFe₁₁O₁₉(s) was also constructed to represent an optimized set of data. - graphical abstract: Variation of standard molar heat capacities of CaLaF₁₁O₁₉(s) and MFe₁₂O₁₉(s) (M=Sr, Ba and Pb) as a function of temperature. Highlights: • Thermodynamic studies on CaLaFe₁₁O₁₉(s) were performed using KEQMS and solution calorimetry. • It was synthesized using gel combustion route and characterized by XRD technique. • The compound is magnetic in nature and shows a heat capacity anomaly at 684 K. • Thermodynamic table was constructed from 298 K to 1000 K.
- OSTI ID:
- 22306268
- Journal Information:
- Journal of Solid State Chemistry, Vol. 201; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
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