Structural Studies and Thermal Analysis in the Cs2MoO4–PbMoO4 System with Elucidation of β‑Cs2Pb(MoO4)2

• Published in: Inorganic chemistry 2023-05, Vol.62 (18), p.6981-6992
• Main Authors: van Hattem, Andries, Vlieland, John, Dankelman, Robert, Thijs, Michel A., Wallez, Gilles, Dardenne, Kathy, Rothe, Jörg, Konings, Rudy J.M., Smith, Anna L.
• Format: Article
• Language: English
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/acs.inorgchem.3c00241

The quaternary compound Cs2Pb­(MoO4)2 was synthesized and its structure was characterized using X-ray and neutron diffraction from 298 to 773 K, while thermal expansion was studied from 298 to 723 K. The crystal structure of the high-temperature phase β-Cs2Pb­(MoO4)2 was elucidated, and it was found to crystallize in the space group R3̅m (No. 166), i.e., with a palmierite structure. In addition, the oxidation state of Mo in the low-temperature phase α-Cs2Pb­(MoO4)2 was studied using X-ray absorption near-edge structure spectroscopy. Phase diagram equilibrium measurements in the Cs2MoO4–PbMoO4 system were performed, revisiting a previously reported phase diagram. The equilibrium phase diagram proposed here includes a different composition of the intermediate compound in this system. The obtained data can serve as relevant information for thermodynamic modeling in view of the safety assessment of next-generation lead-cooled fast reactors.