AS
A. Sacristán Civera
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2 records found
1
Journal article
(2025)
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Dennis C. Alders, Ana Sacristán-Civera, Mädchen Wolff, Elisa Capelli, Eleanor L. Bright, Christoph Hennig, Rudy J.M. Konings, A. L. Smith
In this study, new insights into the solid state chemistry of the systems NaCl-RECl3 (RE = Ce, Nd) are presented, in which the intermediate compound suggested in the literature, i.e. Na3RE5Cl18, is investigated more closely. Our studies have revealed a solubility range around the intermediate composition in the form of the stoichiometry, and have allowed us to revisit the phase diagrams of the NaCl-RECl3 (RE = Ce, Nd) systems accordingly. Furthermore, we demonstrate that among the lanthanide chlorides, NdCl3 is the prime simulant candidate for the melting behaviour of PuCl3-based systems, while CeCl3 is most suited to simulate UCl3-based systems. This is corroborated in this work by comparing the melting profiles of the NaCl-MCl3, MgCl2-MCl3, and NaCl-MgCl2-MCl3 (M = Ce, Nd, U, Pu) systems. In doing so, the binary systems MgCl2-MCl3 (M = Ce, Nd) have been re-visited based on existing data in the literature and estimated mixing enthalpies. Extrapolations to the ternary systems NaCl-MgCl2-RECl3 (RE = Ce, Nd) have been made and compared to the available data in the literature, showing good agreement.
Graphical abstract: Simulant chemistry for uranium and plutonium molten fuel salts: crystallographic investigation and thermodynamic modelling assessment of the NaCl–RECl3 and NaCl-MgCl2-RECl3 (RE = Ce, Nd) systems ...
Graphical abstract: Simulant chemistry for uranium and plutonium molten fuel salts: crystallographic investigation and thermodynamic modelling assessment of the NaCl–RECl3 and NaCl-MgCl2-RECl3 (RE = Ce, Nd) systems ...
In this study, new insights into the solid state chemistry of the systems NaCl-RECl3 (RE = Ce, Nd) are presented, in which the intermediate compound suggested in the literature, i.e. Na3RE5Cl18, is investigated more closely. Our studies have revealed a solubility range around the intermediate composition in the form of the stoichiometry, and have allowed us to revisit the phase diagrams of the NaCl-RECl3 (RE = Ce, Nd) systems accordingly. Furthermore, we demonstrate that among the lanthanide chlorides, NdCl3 is the prime simulant candidate for the melting behaviour of PuCl3-based systems, while CeCl3 is most suited to simulate UCl3-based systems. This is corroborated in this work by comparing the melting profiles of the NaCl-MCl3, MgCl2-MCl3, and NaCl-MgCl2-MCl3 (M = Ce, Nd, U, Pu) systems. In doing so, the binary systems MgCl2-MCl3 (M = Ce, Nd) have been re-visited based on existing data in the literature and estimated mixing enthalpies. Extrapolations to the ternary systems NaCl-MgCl2-RECl3 (RE = Ce, Nd) have been made and compared to the available data in the literature, showing good agreement.
Graphical abstract: Simulant chemistry for uranium and plutonium molten fuel salts: crystallographic investigation and thermodynamic modelling assessment of the NaCl–RECl3 and NaCl-MgCl2-RECl3 (RE = Ce, Nd) systems
Graphical abstract: Simulant chemistry for uranium and plutonium molten fuel salts: crystallographic investigation and thermodynamic modelling assessment of the NaCl–RECl3 and NaCl-MgCl2-RECl3 (RE = Ce, Nd) systems
Journal article
(2025)
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A. van Hattem, L.M.T. de Geus, A. Sacristán Civera, B.J.R. Dankelman, S.D. Couweleers, Christoph Hennig, Jean Christophe Griveau, R. Konings, A.L. Smith, More authors...
The detailed crystal structure as well as the heat capacity at low temperature and standard entropy of Ba2MoO5 are reported for the first time. High-resolution X-ray and neutron diffraction were employed to reveal the structural features of this compound. Ba2MoO5 has a six-coordinated Mo and a strongly negative excess volume with respect to the binary oxides. X-ray absorption near edge structure (XANES) spectroscopy at the Mo K-edge shows Mo to be in the oxidation state 6+. The pre-edge peak in the XANES spectrum indicates a distorted octahedral environment, in line with the results from diffraction studies and FDMNES calculations. The standard entropy and heat capacity of Ba2MoO5 at 298.15 K, determined with a thermal-relaxation technique, are calculated to be respectively 223.2 ± 7 and 184.7 ± 5 J·K–1·mol–1. The obtained thermodynamic properties are discussed in the context of the literature reports on molybdate compounds.
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The detailed crystal structure as well as the heat capacity at low temperature and standard entropy of Ba2MoO5 are reported for the first time. High-resolution X-ray and neutron diffraction were employed to reveal the structural features of this compound. Ba2MoO5 has a six-coordinated Mo and a strongly negative excess volume with respect to the binary oxides. X-ray absorption near edge structure (XANES) spectroscopy at the Mo K-edge shows Mo to be in the oxidation state 6+. The pre-edge peak in the XANES spectrum indicates a distorted octahedral environment, in line with the results from diffraction studies and FDMNES calculations. The standard entropy and heat capacity of Ba2MoO5 at 298.15 K, determined with a thermal-relaxation technique, are calculated to be respectively 223.2 ± 7 and 184.7 ± 5 J·K–1·mol–1. The obtained thermodynamic properties are discussed in the context of the literature reports on molybdate compounds.