Study On The Formability Of Metal Oxides

The majority of semi-metal and transition-metal elements in the periodic table could form ABO3type oxides, while all rare earth elements could form Ln2CO3type oxides, thus the ABO3type metal oxides are very popular in nature. These metal oxides demonstrate excellent physicochemical properties, e.g., catalytic, ferroelectrics, magnetic properties, and receive considerable interests in the scientific fields of heterogeneous catalysis, geophysics, fission and fusion reactors, astrophysical etc.We have defined a stability factor of the perovskite crystal to study the structure stability and formability of the ABO3systems. The values of stability factor were calculated with the Pauling electronegativity and ionic electronegativity, respectively. Regularities governing perovskite formability are investigated, by using the stability factor and empirical structure map methods and a total of241systems (of which162systems can form perovskites). It is found that the stability factor is an important parameter with regard to the formability of ABO3perovskite. On the structure map constructed by the stability factor, sample points representing systems of forming (perovskite) and non-forming, are distributed in distinctively different regions. The stability factor can be used to search for new perovskites by screening all possible elemental combinations in any of the ABO3systems.Prediction criterions for the formability of A2O3-A(2O3oxides are obtained by using the empirical structure map methods constructed by two parameters electronegativity of A and A’ We have applied the proposed model to238A2O3-A’2O3and36new systems are used to validate these empirical rules, and the prediction is in good agreement with experiment.