Oxygen configurations in silica

We propose a transition state for oxygen in silica. This state is produced by the insertion of an oxygen molecule into the Si-O-Si bond, i.e., it cons ists of producing a Si-O-O-O-Si bond. This state allows molecular oxygen di ffusion in silica without breaking the molecular O-2 bond and it is energet ically more stable than a peroxy configuration. This configuration may allo w for exchange of molecular oxygen with the oxygen in the silica framework.