Thermodynamics of Cr2O3, FeCr2O4, ZnCr2O4 and CoCr2O4
High temperature heat capacity measurements were obtained for Cr{sub 2}O{sub 3}, FeCr{sub 2}O{sub 4}, ZnCr{sub 2}O{sub 4} and CoCr{sub 2}O{sub 4} using a differential scanning calorimeter. These data were combined with previously-available, overlapping heat capacity data at temperatures up to 400 K and fitted to 5-parameter Maier-Kelley C{sub p}(T) equations. Expressions for molar entropy were then derived by suitable integration of the Maier-Kelley equations in combination with recent S{sup o}(298) evaluations. Finally, a database of high temperature equilibrium measurements on the formation of these oxides was constructed and critically evaluated. Gibbs energies of Cr{sub 2}O{sub 3}, FeCr{sub 2}O{sub 4} and CoCr{sub 2}O{sub 4} were referenced by averaging the most reliable results at reference temperatures of 1100, 1400 and 1373 K, respectively, while Gibbs energies for ZnCr{sub 2}O{sub 4} were referenced to the results of Jacob [Thermochim. Acta 15 (1976) 79-87] at 1100 K. Thermodynamic extrapolations from the high temperature reference points to 298.15 K by application of the heat capacity correlations gave {Delta}{sub f}G{sup o}(298) = -1049.96, -1339.40, -1428.35 and -1326.75 kJ mol{sup -1} for Cr{sub 2}O{sub 3}, FeCr{sub 2}O{sub 4}, ZnCr{sub 2}O{sub 4} and CoCr{sub 2}O{sub 4}, respectively.
- Research Organization:
- Knolls Atomic Power Lab. (KAPL), Niskayuna, NY (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- DE-AC12-00SN39357
- OSTI ID:
- 903084
- Report Number(s):
- LM-06K145; JCTDAF; TRN: US200720%%73
- Journal Information:
- Journal of Chemical Thermodynamics, Journal Name: Journal of Chemical Thermodynamics; ISSN 0021-9614
- Country of Publication:
- United States
- Language:
- English
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