Abstract
We present neutron powder diffraction results which give unambiguous evidence for the formation of the recently identified new crystalline ice phase [[2]], labeled ice XII, in completely different conditions. Ice XII is produced here by compressing hexagonal ice at , 100, 140, and 160 K up to 1.8 GPa. It can be maintained at ambient pressure in the temperature range . Accurate structural properties are obtained from high-resolution diffraction carried out at . At and 160 K additionally ice III/IX is formed. The increasing amount of ice III/IX with increasing temperature gives an upper limit of for the successful formation of ice XII with the presented procedure.
- Received 20 September 1999
DOI:https://doi.org/10.1103/PhysRevLett.84.4112
©2000 American Physical Society