TY - JOUR
T1 - Energetics of a uranothorite (Th1-xUxSiO4) solid solution
AU - Guo, Xiaofeng
AU - Szenknect, Stéphanie
AU - Mesbah, Adel
AU - Clavier, Nicolas
AU - Poinssot, Christophe
AU - Wu, Di
AU - Xu, Hongwu
AU - Dacheux, Nicolas
AU - Ewing, Rodney C.
AU - Navrotsky, Alexandra
N1 - Funding Information:
Calorimetric measurements at the University of California at Davis and later analyses of data were supported by the Materials Science of Actinides, an Energy Frontier Research Center, funded by the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences, under Grant DE-SC0001089. X.G. was also supported by a Seaborg postdoctoral fellowship from the Laboratory Directed Research and Development (LDRD) program, through the G. T. Seaborg Institute, of Los Alamos National Laboratory (LANL), which is operated by Los Alamos National Security LLC, under DOE Contract DE-AC52-06NA25396. The experiments associated with the preparation and characterization of single-phase and homogeneous uranothorite solid solutions were supported by the NEEDS Resources program of the CNRS (French National Center for Scientific Research).
Publisher Copyright:
© 2016 American Chemical Society.
PY - 2016/10/11
Y1 - 2016/10/11
N2 - High-temperature oxide melt solution calorimetric measurements were completed to determine the enthalpies of formation of the uranothorite, (USiO4)x-(ThSiO4)1-x, solid solution. Phase-pure samples with x values of 0, 0.11, 0.21, 0.35, 0.71, and 0.84 were prepared, purified, and characterized by powder X-ray diffraction, electron probe microanalysis, thermogravimetric analysis and differential scanning calorimetry coupled with in situ mass spectrometry, and high-temperature oxide melt solution calorimetry. This work confirms the energetic metastability of coffinite, USiO4, and U-rich intermediate silicate phases with respect to a mixture of binary oxides. However, variations in unit cell parameters and negative excess volumes of mixing, coupled with strongly exothermic enthalpies of mixing in the solid solution, suggest short-range cation ordering that can stabilize intermediate compositions, especially near x = 0.5.
AB - High-temperature oxide melt solution calorimetric measurements were completed to determine the enthalpies of formation of the uranothorite, (USiO4)x-(ThSiO4)1-x, solid solution. Phase-pure samples with x values of 0, 0.11, 0.21, 0.35, 0.71, and 0.84 were prepared, purified, and characterized by powder X-ray diffraction, electron probe microanalysis, thermogravimetric analysis and differential scanning calorimetry coupled with in situ mass spectrometry, and high-temperature oxide melt solution calorimetry. This work confirms the energetic metastability of coffinite, USiO4, and U-rich intermediate silicate phases with respect to a mixture of binary oxides. However, variations in unit cell parameters and negative excess volumes of mixing, coupled with strongly exothermic enthalpies of mixing in the solid solution, suggest short-range cation ordering that can stabilize intermediate compositions, especially near x = 0.5.
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U2 - 10.1021/acs.chemmater.6b03346
DO - 10.1021/acs.chemmater.6b03346
M3 - Article
AN - SCOPUS:84991320893
SN - 0897-4756
VL - 28
SP - 7117
EP - 7124
JO - Chemistry of Materials
JF - Chemistry of Materials
IS - 19
ER -