Thermodynamic properties of cerium molybdate

Abstract

AbstractCe2(MoO4)3 is a harmful phase formed in waste glasses from nuclear fuel. To determine the third-law entropy of Ce2(MoO4)3, the isobaric heat capacities, $C_{p,m}^^\circ $, were measured with a relaxation-method instrument at 2–300 K. The standard entropy, $\Delta _0^TS_{\rm{m}}^^\circ $, at 298.15 K was determined with fitting functions including the Debye–Einstein formula including electronic and spin-wave terms. The Néel temperature, TN, was estimated by extrapolation from the magnetic term in this fitting function. The phase stability of Ce2(MoO4)3 is discussed in terms of its standard Gibbs energy of formation, ${\Delta _f}G_{\rm{m}}^^\circ $, which was derived by combining the values for $S_m^^\circ $determined in this study with reference data for the standard enthalpy of formation, ${\Delta _f}H_{\rm{m}}^^\circ $.