Prediction of a novel high-pressure phase of hydrogen peroxide

Abstract

The binary H-O system almost exclusively exists in the form of water ice with stoichiometry of ${\mathrm{H}}_{2}\mathrm{O}$ in a wide range of pressure (\ensuremath{\sim}5 TPa) that is one of the most abundant substances in the solar system. Hydrogen peroxide (${\mathrm{H}}_{2}{\mathrm{O}}_{2}$) is only metastable at ambient condition. We herein report a stable ${\mathrm{H}}_{2}{\mathrm{O}}_{2}$ phase at high pressure identified by first-principles calculations in combination with a swarm-intelligence structure search. The predicted ${\mathrm{H}}_{2}{\mathrm{O}}_{2}$ compound is formed by stacking of an intriguing planar ${\mathrm{H}}_{2}{\mathrm{O}}_{2}$ molecule different from the metastable three-dimensional isomer at ambient condition. The planarity of hydrogen peroxide molecules is expected to be caused by the steric repulsion between molecules at high pressure, which is responsible for the stability of the crystal. The phase is energetically stable in the pressure range of \ensuremath{\sim}423--600 GPa. It is thus a low-pressure phase of binary H-O system with H:O stoichiometry other than 2:1 and promises to be accessible in static compression experiment.