Structure of water from ambient to 4Â GPa revealed by energy-dispersive X-ray diffraction combined with empirical potential structure refinement modeling

► X-ray diffraction measurements were made on water at 298 ~ 486 K and 0.1 MPa ~ 4 GPa. ► Empirical potential structure refinement modeling was applied to the X-ray structure factors. ► The tetrahedral moiety of water molecules was disrupted in the subcritical condition due to the collapsed second shell. ► The structure of water at several GPa approaches that of simple liquids.