Heat capacities and absolute entropies of UTi2O6 and CeTi2O6

M. Donaldson, Rebecca Stevens, B. E. Lang, Juliana Boerio-Goates, B. F. Woodfield, R. L. Putnam, Alexandra Navrotsky

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9 Scopus citations

Abstract

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 (CeTi2O 6) 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 CeTi 2O6, 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 CeTi2O 6, respectively.

Original languageEnglish (US)
Pages (from-to)617-625
Number of pages9
JournalJournal of Thermal Analysis and Calorimetry
Volume81
Issue number3
DOIs
StatePublished - Aug 2005
Externally publishedYes

Keywords

  • Brannerite
  • CeTiO
  • Enthalpy
  • Entropy
  • Heat capacity
  • Thermodynamic functions
  • Thermodynamics
  • UTiO

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

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