Inorganic Chemistry
Article
role during the formation of ThSiO under such acidic con-
ditions.
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(
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. CONCLUSION
(
The preparation of ThSiO under hydrothermal conditions was
4
(
performed for 24 h of holding time by varying several
parameters, including temperature, pH, and thorium and silicon
concentrations in the starting solution. From these results, it
(
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may be inferred that the ThSiO formation is favored for high
4
temperatures and reagent concentrations. Pure ThSiO samples
4
were formed, provided that
(
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+
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(
(
(
1) the initial pH ranged from [H O ] = 0.3 mol L to
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(
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4
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4
(
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2
2
(
of ThSiO in the less acidic studied media was explained by the
4
̈
rapid hydrolysis of thorium, leading to the precipitation of
thorium tetrahydroxide and then to the formation of thorium
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(
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ASSOCIATED CONTENT
Supporting Information
■
(
*
S
(
Figure S1 compiling the data present in Table 2 to
represent the evolution of the thorite lattice parameters as
a function of the temperature of hydrothermal synthesis,
Figure S2 representing the evolution of the thorite lattice
parameters as a function of the thorium concentration in
the reactive media, Figure S3 presenting the thorium and
silicon solubility diagram determined by PhreeqC
calculations, Table S1 containing the thermodynamic
data reported in the literature for the thorium and silicon
species, and Table S2 reporting the synthesis parameters
4
2
(
Szenknect, S.; Ravaux, J. How to explain the difficulties in the coffinite
synthesis from the study of uranothorite? Inorg. Chem. 2011, 50,
1
1117−11126.
(20) Costin, D. T. Solutions solides d’uranothorite: de la prep
dissolution, Ph.D. Thesis; Universite
France, 2012.
́
aration a
́
de Montpellier 2, Montpellier,
̀
la
(21) Costin, D. T.; Mesbah, A.; Clavier, N.; Szenknect, S.; Dacheux,
N.; Poinssot, C.; Ravaux, J.; Brau, H. P. Preparation and character-
for all of the ThSiO hydrothermal syntheses presented
4
ization of synthetic Th U SiO uranothorite. Prog. Nucl. Energy 2012,
0
.5 0.5
4
5
(
7, 155−160.
22) Clavier, N.; Szenknect, S.; Costin, D. T.; Mesbah, A.; Ravaux, J.;
AUTHOR INFORMATION
Corresponding Author
Poinssot, C.; Dacheux, N. Purification of uranothorite solid solutions
■
from polyphase systems. J. Nucl. Mater. 2013, 441, 73−83.
(23) Szenknect, S.; Costin, D. T.; Clavier, N.; Mesbah, A.; Poinssot,
C.; Vitorge, P.; Dacheux, N. From uranothorites to coffinite: a solid
solution route to the thermodynamic properties of USiO . Inorg. Chem.
4
ORCID
2
013, 52, 6957−6968.
Notes
(24) Clavier, N.; Szenknect, S.; Costin, D. T.; Mesbah, A.; Poinssot,
C.; Dacheux, N. From thorite to coffinite: A spectroscopic study of
Th U SiO solid solutions. Spectrochim. Acta, Part A 2014, 118, 302−
1‑x
x
4
307.
The authors declare no competing financial interest.
(25) Labs, S.; Hennig, C.; Weiss, S.; Curtius, H.; Zanker, H.; Bosbach,
̈
D. Synthesis of coffinite, USiO , and structural investigations of
4
ACKNOWLEDGMENTS
The authors thank R. Podor, J. Lautru, and V. Trillaud (from the
ICSM) for supporting SEM experiments.
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U Th SiO solid solutions. Environ. Sci. Technol. 2014, 48, 854−860.
x
(1‑x)
4
(26) Pointeau, V.; Deditius, A. P.; Miserque, F.; Renock, D.; Becker,
U.; Zhang, J.; Clavier, N.; Dacheux, N.; Poinssot, C.; Ewing, R. C.
I
Inorg. Chem. XXXX, XXX, XXX−XXX