Standard Gibbs energy of formation of Mo3Te4 by emf measurements

The emf of the galvanic cells Pt, Mo, MoO₂¦8 YSZ¦‘FeO’, Fe, Pt (I) and Pt, Fe,‘FeO’ ¦8 YSZ¦MoO₂, Mo₃Te₄, MoTe₂(), C, Pt (II) were measured over the temperature ranges 837 to 1151 K and 775 to 1196 K, respectively, using 8 mass% yttria-stabilized zirconia (8 YSZ) as the solid electrolyte. From the emf values, the partial molar Gibbs energy of solution of molybdenum in Mo₃Te₄/MoTe₂(), was found to be

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. Using the literature data for the Gibbs energy of formation of MoTe₂(). the expression ΔG°_f(Mo₃Te_4,s) ± 5.97 (kj/mol) = ?253.58 + 0.09214T(K) was derived for the range 775 to 1196 K. A third-law analysis yielded a value of ?209 ± 10 kJ/mol for ΔH°_f.298^o of Mo₃Te₄(s).