The ternary cesium molybdates Cs2Mo2O7, Cs2Mo3O10, Cs2Mo5O16 and Cs2Mo7O22 have been synthesized in this work using a solid state route and their structures have been characterized using X-ray diffraction. The enthalpies of formation of Cs2Mo2O7 and Cs2Mo3O10 have been measured using solution calorimetry, yielding ΔfHmo(Cs2Mo2O7, cr, 298.15 K) = −(2301.6 ± 4.7) kJ · mol−1 and ΔfHmo(Cs2Mo3O10, cr, 298.15 K) = −(3075.6 ± 6.5) kJ · mol−1, respectively. In addition, the transition temperatures and transition enthalpies of Cs2Mo2O7, Cs2Mo3O10, Cs2Mo5O16 and Cs2Mo7O22 have been determined using differential scanning calorimetry. Finally, phase diagram equilibria measurements in the Cs2MoO4-MoO3 pseudo-binary section have been performed, that have yielded generally slightly lower transition temperatures than reported in previous studies. Those data can serve as valuable input for thermodynamic modelling purposes of the fission products chemistry in Light Water Reactors and next generation Sodium-cooled Fast Reactors and Lead-cooled Fast Reactors.
- Cesium polymolybdates
- Differential scanning calorimetry
- Joint oxyde-gaine
- Solution calorimetry