Determination of Gibbs Energies of Formation of CaFe_2O_4 and Ca_2Fe_2O_5 from Solid-State EMF Measurements Using CaF_2 as Solid Electrolyte

摘要

The standard Gibbs energy change for the reactions CaO+Fe_2O_3->CaFe_2O_4 and 2 CaO+Fe_2O_3->Ca_2Fe_2O_5 has been determined from solid-state electromotive force (emf) measurements, using CaF_2 as solid electrolyte. The temperature dependence of the standard Gibbs energies of formation from the elements is represented by the equationsDELTA_fG~0(CaFe_2O_4)=-1448.4X10~3+128.0T+27.95T ln(T) (+-1800) J mol~(-1)1030