STRUCTURE, MECHANICAL STABILITY, AND CHEMICAL BOND IN ALKALI METAL OXIDES

Crystal structure parameters, elastic constants, atomic charges, and deformation density distributions of lithium, sodium, potassium, rubidium oxides, peroxides, superoxides, and ozonides are calculated with the use of the CRYSTAL06 program package in the LCAO basis in the LDA and GGA approximation of density functional theory. The obtained characteristics are found to be in good agreement with the experimental data and calculations of the other authors. All crystals, except sodium, potassium, and rubidium superoxides, are shown to correspond to mechanical stability conditions. The chemical bond between the cation and anion has the ionic character and pi-type covalent in the anion. A distinctive feature of its formation is the charge flow from the bond to the toroidal region oriented perpendicularly to the O-O line with the center on the oxygen atom nucleus.