Pressure suppression of charge order without metallisation in Cs2Au2I6

Resistivity and powder X-ray diffraction measurements on Cs2Au2I6 up to 320 kbar pressure show that the suppression of Au+/Au3+ charge order above 55 kbar results in a non-metallic phase containing localised Au2+ states that is irreversibly amorphised above 120 kbar, and a gradual metallisation observed above 175 kbar may result from decomposition within the amorphous material.