Knowledge Bank

The vaporization into vacuum of the sesquioxides $Y2O2$, $La2O3$, and $Ce2O3$ was studied between 2000 and $2500\circ K$. The major components of the gas phase are the respective metal monoxides YO, LaO, CeO and oxygen. From the rates of evaporation the partial pressures of the gaseous monoxides in equilibrium with the solid sesquioxides can be calculated. These values combined with known thermochemical quantities, permits calculation of the dissociation energies $Doo$ of the monoxides.