Paper detail

Lattice parameters and stability of the spinel compounds in relation to the ionic radii and electronegativities of constituting chemical elements

A thorough consideration of the relation between the lattice parameters of 185 binary and ternary spinel compounds, on one side, and ionic radii and electronegativities of the constituting ions, on the other side, allowed for establishing a simple empirical model and finding its linear equation, which links together the above-mentioned quantities. The derived equation gives good agreement between the experimental and modeled values of the lattice parameters in the considered group of spinels, with an average relative error of about 1% only. The proposed model was improved further by separate consideration of several groups of spinels, depending on the nature of the anion (oxygen, sulfur, selenium/tellurium, nitrogen). The developed approach can be efficiently used for prediction of lattice constants for new isostructural materials. In particular, the lattice constants of new hypothetic spinels ZnRE2O4, CdRE2S4, CdRE2Se4 (RE=rare earth elements) are predicted in the present paper. In addition, the upper and lower limits for the variation of the ionic radii, electronegativities and certain their combinations were established, which can be considered as stability criteria for the spinel compounds. The findings of the present paper offer a systematic overview of the structural properties of spinels and can serve as helpful guides for synthesis of new spinel compounds.