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Journal of Thermal Analysis and Calorimetry

, Volume 81, Issue 3, pp 617–625 | Cite as

Heat capacities and absolute entropies of UTi2O6 and CeTi2O6

  • M. Donaldson
  • Rebecca Stevens
  • B. E. Lang
  • Juliana Boerio-Goates
  • B. F. Woodfielda
  • R. L. Putnam
  • Alexandra Navrotsky
Article

Summary

As part of a larger study of the physical properties of potential ceramic hosts for nuclear wastes, we report the molar heat capacity of brannerite (UTi2O6) and its cerium analog (CeTi2O6) from 10 to 400 K using an adiabatic calorimeter. At 298.15 K the standard molar heat capacities are (179.46±0.18) J K-1 mol-1 for UTi2O6  and (172.78±0.17) J K-1 mol-1 for CeTi2O6. Entropies were calculated from smooth fits of the experimental data and were found to be (175.56±0.35) J K-1 mol-1 and (171.63±0.34) J K-1 mol-1 for UTi2O6 and CeTi2O6, respectively. Using these entropies and enthalpy of formation data reported in the literature, Gibb’s free energies of formation from the elements and constituent oxides were calculated. Standard free energies of formation from the elements are (-2814.7±5.6) kJ mol-1 for UTi2O6 and (-2786.3±5.6) kJ mol-1 for CeTi2O6. The free energy of formation from the oxides at T=298.15 K are (-5.31±0.01) kJ mol-1 and (15.88±0.03) kJ mol-1 for UTi2O6 and CeTi2O6, respectively.

enthalpy entropy thermodynamics heat capacity thermodynamic functions brannerite CeTi2O6 UTi2O6 

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Copyright information

© Springer-Verlag/Akadémiai Kiadó 2005

Authors and Affiliations

  • M. Donaldson
    • 1
  • Rebecca Stevens
    • 2
  • B. E. Lang
    • 3
  • Juliana Boerio-Goates
    • 4
  • B. F. Woodfielda
    • 5
  • R. L. Putnam
    • 6
  • Alexandra Navrotsky
    • 7
  1. 1.Department of Chemistry and Biochemistry, Brigham Young University
  2. 2.Department of Chemistry and Biochemistry, Brigham Young University
  3. 3.Department of Chemistry and Biochemistry, Brigham Young University
  4. 4.Department of Chemistry and Biochemistry, Brigham Young University
  5. 5.Department of Chemistry and Biochemistry, Brigham Young University
  6. 6.Thermochemistry Facility, Department of Chemical Engineering and Materials Science, University of California
  7. 7.Thermochemistry Facility, Department of Chemical Engineering and Materials Science, University of California

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