Determination of the standard Gibbs free energies of formation of the silicates of cobalt,magnesium, and strontium by e.m.f. measurements

Standard Gibbs free energies of formation of the silicates in the quasi-binaries: CoO and SiO₂, MgO and SiO₂, and SrO and SiO₂ were determined with the help of solid-state galvanic cells in the temperature ranges 1273 to 1673 K, 1373 to 1573 K, and 1323 to 1473 K, respectively. Stabilized ZrO₂ was used as an electrolyte for the CoO and SiO₂ system. For the MgO and SiO₂ system MgF₂, and for the SrO and SiO₂ system SrF₂, was used as an electrolyte embedded in a silicate-matrix phase.