No abstract

No abstract

The emf of the following galvanic cells with stabilized zirconia solid electrolyte was measured to determine the calcium antimonites which can coexist with liquid antimony in the temperature range 930−1100 K; (−)Pt, Re|Sb(1), two phases in CaO‐Sb2O3 system | O2− | air, Pt(+) Equilibrium oxygen pressures are obtained as follows: 3/2RT In PO2/kJ = −687.5+0.2433 T/K±0.6 for Sn, Sb2O3; −817.8+0.2402T/K±0.6 for Sb(1), 4CaO·Sb2O3, CaO; −800.5+0.2463T/K±0.6 for Sb(1), 4CaO·Sb2O3, 2CaO·Sb2O3; −762.5+0.2828T/K±0.5 for Sb(1), 2CaO·Sb2O3, CaO·Sb2O3; −690.5+0.2436T/K±1.0 for Sb(1), CaO·Sb2O3, Sb2O3. Standard Gibbs free energies of formation of double oxides coexisting with liquid antimony from CaO(s) and Sb2O3 are derived as follows: 4CaO(s)+Sb2O3(1)=4CaO·Sb2O3(s); ΔG°/kJ = −130.3−0.0031 T/K 2CaO(s)+Sb2O3(1)=2CaO·Sb2O3(s); ΔG°/kJ = −121.7−0.00005 T/K CaO(s)+Sb2O3(1)=CaO·Sb2O3(s); ΔG°/kJ = −98.3+0.0197 T/K. The activities of Sb2O3 and CaO in the two phase regions at 1000 and 1100 K are derived and the most stable double oxide is CaO·Sb2O3 in this system. By an X‐ray diffractometry, it was found that 3CaO·Sb2O3(s) cannot coexist with Sb(1).

No abstract

No abstract