The quaternary compound Cs2Pb(MoO4)2was 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)2was elucidated,
and it was found to crystallize in the space groupR3̅m(No. 166), i.e., with a palmierite structure.
In addition, the oxidation state of Mo in the low-temperature phase
α-Cs2Pb(MoO4)2was studied
using X-ray absorption near-edge structure spectroscopy. Phase diagram
equilibrium measurements in the Cs2MoO4–PbMoO4system 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.