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Title: Thermodynamic studies on SrFe{sub 12}O{sub 19}(s), SrFe{sub 2}O{sub 4}(s), Sr{sub 2}Fe{sub 2}O{sub 5}(s) and Sr{sub 3}Fe{sub 2}O{sub 6}(s)

Abstract

The citrate-nitrate gel combustion route was used to prepare SrFe{sub 2}O{sub 4}(s), Sr{sub 2}Fe{sub 2}O{sub 5}(s) and Sr{sub 3}Fe{sub 2}O{sub 6}(s) powders and the compounds were characterized by X-ray diffraction analysis. Different solid-state electrochemical cells were used for the measurement of emf as a function of temperature from 970 to 1151K. The standard molar Gibbs energies of formation of these ternary oxides were calculated as a function of temperature from the emf data and are represented as {delta}{sub f}G{sub m}{sup o} (SrFe{sub 2}O{sub 4}, s, T)/kJmol{sup -1} (+/-1.7)=-1494.8+0.3754(T/K) (970=<T/K=<1151). {delta}{sub f}G{sub m}{sup o} (Sr{sub 2}Fe{sub 2}O{sub 5}, s, T)/kJmol{sup -1} (+/-3.0)=-2119.3+0.4461(T/K) (970=<T/K=<1149). {delta}{sub f}G{sub m}{sup o} (Sr{sub 3}Fe{sub 2}O{sub 6}, s, T)/kJmol{sup -1} (+/-7.3)=-2719.8+0.4974(T/K) (969=<T/K=<1150). Standard molar heat capacities of these ternary oxides were determined from 310 to 820K using a heat flux type differential scanning calorimeter (DSC). Based on second law analysis and using the thermodynamic database FactSage software, thermodynamic functions such as {delta}{sub f}H{sup o}(298.15K), S{sup o}(298.15K) S{sup o}(T), C{sub p}{sup o}(T), H{sup o}(T), {l_brace}H{sup o}(T)-H{sup o}(298.15K){r_brace}, G{sup o}(T), free energy function (fef), {delta}{sub f}H{sup o}(T) and {delta}{sub f}G{sup o}(T) for these ternary oxides were also calculated from 298 to 1000K.

Authors:
 [1];  [2];  [2];  [2];  [2];  [2]
  1. Product Development Section, RC and I Group, Bhabha Atomic Research Centre, Trombay, Mumbai-400085 (India), E-mail: swarup_kr@rediffmail.com
  2. Product Development Section, RC and I Group, Bhabha Atomic Research Centre, Trombay, Mumbai-400085 (India)
Publication Date:
OSTI Identifier:
21015679
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 180; Journal Issue: 2; Other Information: DOI: 10.1016/j.jssc.2006.11.012; PII: S0022-4596(06)00597-4; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CALORIMETERS; CALORIMETRY; CITRATES; COMBUSTION; COMPUTER CODES; CURIE POINT; ELECTROCHEMICAL CELLS; ELECTROMOTIVE FORCE; FERRITES; FREE ENERGY; GELS; HEAT FLUX; NITRATES; SPECIFIC HEAT; STRONTIUM COMPOUNDS; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 0273-0400 K; TEMPERATURE RANGE 0400-1000 K; X-RAY DIFFRACTION

Citation Formats

Rakshit, S.K., Parida, S.C., Dash, S., Singh, Z., Sen, B.K., and Venugopal, V. Thermodynamic studies on SrFe{sub 12}O{sub 19}(s), SrFe{sub 2}O{sub 4}(s), Sr{sub 2}Fe{sub 2}O{sub 5}(s) and Sr{sub 3}Fe{sub 2}O{sub 6}(s). United States: N. p., 2007. Web. doi:10.1016/j.jssc.2006.11.012.
Rakshit, S.K., Parida, S.C., Dash, S., Singh, Z., Sen, B.K., & Venugopal, V. Thermodynamic studies on SrFe{sub 12}O{sub 19}(s), SrFe{sub 2}O{sub 4}(s), Sr{sub 2}Fe{sub 2}O{sub 5}(s) and Sr{sub 3}Fe{sub 2}O{sub 6}(s). United States. doi:10.1016/j.jssc.2006.11.012.
Rakshit, S.K., Parida, S.C., Dash, S., Singh, Z., Sen, B.K., and Venugopal, V. Thu . "Thermodynamic studies on SrFe{sub 12}O{sub 19}(s), SrFe{sub 2}O{sub 4}(s), Sr{sub 2}Fe{sub 2}O{sub 5}(s) and Sr{sub 3}Fe{sub 2}O{sub 6}(s)". United States. doi:10.1016/j.jssc.2006.11.012.
@article{osti_21015679,
title = {Thermodynamic studies on SrFe{sub 12}O{sub 19}(s), SrFe{sub 2}O{sub 4}(s), Sr{sub 2}Fe{sub 2}O{sub 5}(s) and Sr{sub 3}Fe{sub 2}O{sub 6}(s)},
author = {Rakshit, S.K. and Parida, S.C. and Dash, S. and Singh, Z. and Sen, B.K. and Venugopal, V.},
abstractNote = {The citrate-nitrate gel combustion route was used to prepare SrFe{sub 2}O{sub 4}(s), Sr{sub 2}Fe{sub 2}O{sub 5}(s) and Sr{sub 3}Fe{sub 2}O{sub 6}(s) powders and the compounds were characterized by X-ray diffraction analysis. Different solid-state electrochemical cells were used for the measurement of emf as a function of temperature from 970 to 1151K. The standard molar Gibbs energies of formation of these ternary oxides were calculated as a function of temperature from the emf data and are represented as {delta}{sub f}G{sub m}{sup o} (SrFe{sub 2}O{sub 4}, s, T)/kJmol{sup -1} (+/-1.7)=-1494.8+0.3754(T/K) (970=<T/K=<1151). {delta}{sub f}G{sub m}{sup o} (Sr{sub 2}Fe{sub 2}O{sub 5}, s, T)/kJmol{sup -1} (+/-3.0)=-2119.3+0.4461(T/K) (970=<T/K=<1149). {delta}{sub f}G{sub m}{sup o} (Sr{sub 3}Fe{sub 2}O{sub 6}, s, T)/kJmol{sup -1} (+/-7.3)=-2719.8+0.4974(T/K) (969=<T/K=<1150). Standard molar heat capacities of these ternary oxides were determined from 310 to 820K using a heat flux type differential scanning calorimeter (DSC). Based on second law analysis and using the thermodynamic database FactSage software, thermodynamic functions such as {delta}{sub f}H{sup o}(298.15K), S{sup o}(298.15K) S{sup o}(T), C{sub p}{sup o}(T), H{sup o}(T), {l_brace}H{sup o}(T)-H{sup o}(298.15K){r_brace}, G{sup o}(T), free energy function (fef), {delta}{sub f}H{sup o}(T) and {delta}{sub f}G{sup o}(T) for these ternary oxides were also calculated from 298 to 1000K.},
doi = {10.1016/j.jssc.2006.11.012},
journal = {Journal of Solid State Chemistry},
number = 2,
volume = 180,
place = {United States},
year = {Thu Feb 15 00:00:00 EST 2007},
month = {Thu Feb 15 00:00:00 EST 2007}
}