High-pressure high-temperature synthesis of Rh2O3-II-type In2O3 polymorph

The metastability of the bixbyite- and corundum-type In2O3 polymorphs up to 33 GPa (at room temperature) is shown. While compressed (in diamond anvil cells) and laser-heated, both polymorphs undergo a phase transition to the Rh2O3-II-type structure (space group Pbcn, No. 60). The direct transition from bixbyite to Rh2O3-II structure has not yet been observed for any other oxide