Oxygen incorporation into alpha-Al2O3 was examined using electronic structure techniques. It was demonstrated that the ground-state configuration was a peroxide split interstitial, which was more than 2eV lower in energy than the oxide closed-shell interstitial species in alumina, which proves to be only a transition state. The results had general implications for the nature of oxygen interstitials in close-packed oxides.

Oxygen Interstitial Structures in Close-Packed Metal Oxides. A.A.Sokol, A.Walsh, C.R.A.Catlow: Chemical Physics Letters, 2010, 492[1-3], 44-8