Thermodynamic investigation on MTe2O6 (M = Th, Ce)

The standard Gibbs energies of formation of MTe2O6 (s) (where M = Th, Ce) were derived from vapour pressure measurements by employing thermogravimetry (TG) based transpiration technique. The vapour pressures of TeO2 (g) over the mixtures MTe2O6 (s) + MO2 (s) generated by the incongruent vapourisation reaction, MTe2O6 (s) → MO2 (s) + 2 TeO2 (g) were measured in the temperature range 1034–1167 K and 986–1129 K for ThTe2O6 (s) and CeTe2O6 (s) respectively. From the vapour pressure measurements the standard Gibbs energies of formation of MTe2O6 (s) were derived. The derived values of Δf G∘ < ThTe2O6, s > and Δf G∘ < CeTe2O6, s > were combined with free energy functions to obtain Δf H 298 K ∘ of ThTe2O6 (s) and CeTe2O6 (s).