The heat capacities, C p;m , for SrMoO 4 at 200-300 K were measured by the relaxation method. The third law entropy, S m , and the Debye temperatures, # D , were determined from the measured C p;m . The obtained thermodynamic properties were: S m (SrMoO 4 (cr), 298.15 K)/ J K ¹1 mol ¹1 = 136.56 « 1.37; # D (SrMoO 4 (cr))/K = 373 « 6. Such thermodynamic properties can be used for evaluating the hierarchy for formation of the yellow phase related-substances in the nuclear waste glasses.

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The isobaric heat capacities, C p;m , for BaMoO 4 at 2300 K were measured by the relaxation method. The third law entropy, S m , was determined via the Debye-Einstein function into which the Debye temperature, # D , as physico-chemical constant and a thermal expansion term were incorporated. # D was determined from C p;m at very low temperatures. The obtained thermodynamic properties were: S m (BaMoO 4 (cr), 298.15 K)/J K ¹1 mol ¹1 = 152.69 « 1.53; # D (BaMoO 4 (cr))/K = 295 « 3. The phase stability of BaMoO 4 was discussed on the basis of its standard Gibbs energy of formation, Á f G m . It was derived by combining S m determined in this study with the reference data of the standard enthalpy of formation, Á f H m . The thermodynamic properties obtained in the present study can be used for evaluating the hierarchy for formation of the yellow phase related-substances in nuclear waste glasses.

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