MOLAR GIBBS ENERGY FORMATION OF RBUO3(S)

The molar Gibbs energy of formation of RbUO3(s) was determined by meas uring the oxygen pressure over the phase field, RbUO3(s) + Rb2U2O7(s) + Rb2UO4(s), using a solid oxide electrolyte galvanic cell in the temp erature range 920 to 1100 K and the partial pressure of rubidium using the Knudsen effusion mass loss method in the temperature range 1305 t o 1459 K. The oxygen potential and the rubidium potential existing ove r the phase field can be respectively given by Delta mu(O-2) +/- 0.4(k J mol(-1)) = -531.6 +/- 0.2026T(K) and Delta mu(Rb) +/- 0.6(kJ mol(-1) ) = -152.7 + 0.018T(K).