Ice XV: a new thermodynamically stable phase of ice.
A new phase of ice, named ice XV, has been identified and its structure determined by neutron diffraction. Ice XV is the hydrogen-ordered counterpart of ice VI and is thermodynamically stable at temperatures below approximately 130 K in the 0.8 to 1.5 GPa pressure range. The regions of stability in the medium pressure range of the phase diagram have thus been finally mapped, with only hydrogen-ordered phases stable at 0 K. The ordered ice XV structure is antiferroelectric (P1), in clear disagreement with recent theoretical calculations predicting ferroelectric ordering (Cc).
Department of Chemistry, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom. christoph.salzmann@chem.ox.ac.uk
Christoph G
CG
Salzmann
Paolo G
PG
Radaelli
Erwin
E
Mayer
John L
JL
Finney