Thermodynamics of Cesium Molybdate-Based Single Crystals: Standard Enthalpy of Formation, Lattice Enthalpy, and Heat Capacity

Cs 2 MoO 4 and Li 1.9 Cs 0.1 MoO 4 crystals were grown from melt by the low-thermal-gradient Czochralski technique. The standard formation enthalpy of cesium molybdate Cs 2 MoO 4 was measured by solution calorimetry. The heat capacity of Li 1.9 Cs 0.1 MoO 4 was measured by differential scanning calorimetry (DSC) in the temperature range 320–710 K. The lattice enthalpy of Cs 2 MoO 4 was calculated using the Born-Haber cycle. Cesium molybdate was shown to be thermodynamically stable to decomposition into constituent simple oxides (Cs 2 O and MoO 3 ), which made it promising for application. Li 1.9 Cs 0.1 MoO 4 experienced no phase transitions in the temperature range 320–710 K.