THERMOCHEMICAL AND KINETIC-STUDIES ON CETE2O6

The molar Gibbs energy of formation for CeTe2O6 was derived from its v apour pressure measurements in the temperature range 900-1120 K. CeTe2 O6 vaporizes incongruently, according to the reaction CeTe2O6(s)double left right arrow CeO2(s)+2TeO(2)(g) Vapour pressures of TeO2(g) were measured over a mixture of CeTe2O6(s) and CeO2(s) and over TeO2(1) in the above temperature range by employing the Knudsen effusion mass los s technique. From the partial pressures of TeO2(g) the molar Gibbs fre e energy of formation (Delta(f)G degrees) of CeTe2O6(s) was obtained; it can be represented by the relation Delta(f)G degrees<CeTe2O6,s,T>+/ -20.0 kJ mol(-1) = -1654.8+0.4486T(K) (902<T(K)<1116) The kinetics of decomposition under isothermal heating conditions in flowing air were studied to determine the rate constants, activation energy and reactio n mechanism.