Fig. 2: Phase diagram at negative to intermediate pressure.
From: Open questions on the structures of crystalline water ices
Stable phases of ice and liquid water up to 2.5 GPa and 400 K, excluding water vapour and metastable phases. Dashed lines indicate extrapolations based on experiments at higher temperature. Dotted lines at negative pressure are sketched based on simulations by Conde et al. in ref. 9 and shifted to match experimental data at positive pressure. Grey indicates liquid water. Blue indicates H-ordered ices, orange/red indicates H-disordered ices. Shades of colour indicate density. Predicted low-density ice polymorphs as candidates for future experimental discovery derived from clathrate hydrate and zeolite structures are listed at the far negative pressure end.
