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 - 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 -