Synchrotron X-ray diffraction study for crystal structure of solid carbon dioxide CO2-V

Abstract

Synchrotron X-ray diffraction study for solid CO2 at 40-100 GPa and around 2,000 K has shown that the diffraction pattern of the high pressure phase CO2-V is consistently interpreted in terms of a tetragonal uni-t cell (Z 4, a 3.584, c 5.908 at 50GPa). A β-cristobalite structure (space group I4̄2d) gives a good account of our data qualitatively. Isothermal molar volume (300K) of the CO2-V in the present study is smaller than that indexed as a tridymite structure proposed by previous studies at any pressures. © 2010 IOP Publishing Ltd.