Electrical conductivity measurement for estimation of standard Gibbs energy change of ternary oxide formation

Electrical conductivity measurements are used here to estimate the Gibbs en ergy change for formation of ternary oxide from binary oxides. The theoreti cal background and the advantages of the present method are discussed. As a demonstration, the standard Gibbs energy change of the reaction, Sr3Cr2O8 + 1/2Cr(2)O(3) +5/4O(2) --> 3SrCrO(4) was estimated by electrical conductivity measurements of two kinds of SrCrO 4 oxides, one equilibrated with Sr3Cr2O8 and the other with Cr2O3. The stan dard Gibbs energy change of the reaction is obtained as DeltaG degrees /kJ mol(-1) = -409 + 0.252T (+/-10), 1323 similar to 1373 K. The resulting value is in good agreement with that obtained by measurement of the equilibrium oxygen pressure using a solid oxygen concentration cell.