EVIDENCE FOR A NEW PHASE OF WATER - WATER-II

Unstable glassy solid forms of water can be made by vapor deposition or by splat quenching the liquid. When they are annealed at about 130 K, both of the amorphous solids evidently relax into the same metastable amorphous state, which behaves reproducibly on thermal cycling and displays an apparent glass transition at 136 K to a liquid which freezes (irreversibly) to ice (1c) at 150 K. The apparently liquid water at 150 K cannot be a metastable extension of normal liquid water unless its entropy is implausibly small. I conclude that it is a distinct metastable amorphous phase of water, which I call water II. Entropy estimates indicate that water II would be, t thermodynamically, the most stable form of water at some temperature above 150 K unless it becomes absolutely unstable at some upper temperature limit of stability.