The structure of a new phase of ice

摘要: Ice has eleven known crystalline phases (Fig. 1), in which the watermolecules are linked through hydrogen bonds into tetrahedralframeworks1. Thisuncommonly large number of different solid attests to thestructural versatility water molecule. Here we reportthe identification a new, twelfth phase ice inthe pressure range 0.2–0.6 GPa. Thetopology this is unlike that any knownphases, and contains mixture five- seven-membered ringsof molecules. It density similar iceIV, also occurs within thestability region V. Both likely bemetastable with respect less-dense This ofthe diagram thus provides potential model system forexperimental theoretical studies ofmetastability.