Cyclic Ozone Identified in Magnesium Oxide (111) Surface Reconstructions

We report the first experimental evidence of the cyclic form of ozone, found in three air stable surface reconstructions of MgO (111) annealed above 1450 °C. The $\mathrm{MgO}\left(111\right)-(\sqrt{3}\times \sqrt{3})R30\mathrm{}°$ surface consists of equilateral oxygen trimers while the $\mathrm{MgO}\left(111\right)-(2\times 2)$ and $\mathrm{MgO}\left(111\right)-(2\sqrt{3}\times 2\sqrt{3})R30\mathrm{}°$ surfaces are periodic arrangements of trimers and single oxygen atoms. The oxygen trimers appear to be centered over underlying Mg atoms. The structures fit transmission electron diffraction data better than neutral plane faceting based models proposed for the polar MgO (111) surface.