Before revision: At each given pressure-temperature conditions, for any compound or element M that bears the potential to be oxidized by oxygen , we can write For example, if M is Fe, the redox equilibrium reaction can be Fe+1/2O2=FeO; if M is FeO, the redox equilibrium reaction can be 2FeO+1/2O2=Fe2O3.
After revision: At each given pressure-temperature conditions, for any compound or element M that bears the potential to be oxidized by oxygen For example, if M is Fe, the redox equilibrium reaction can be Fe+1/2O2=FeO; if M is FeO, the redox equilibrium reaction can be 2FeO+1/2O2=Fe2O3.