ABSTRACT
Equilibrium states are described by the laws of chemical thermodynamics, and the term thermodynamics was introduced by Lord Kelvin as “the relation of heat to forces acting between contiguous parts of bodies”. One can summarize that the thermodynamic stability of oxides is mainly determined by the equilibria of the corresponding metals with oxygen. Cuprite Cu2O is one of the oxides where semiconducting properties could be observed, and it belongs to the small group of p-type transparent semiconducting oxides. Thermodynamic data for simple oxides and other simple compounds such as halides or chalcogenides are often available in the original literature or in compilations, whereas data for more complex substances such as oxides of two or more metals are scarce. For oxides, this means that every oxidation level from zero to a maximum of eight has a limited phase field in the coordinates temperature T and oxygen fugacity partial pressure.
