Superionic Ice...

Structure of superionic ice in (left) the bcc phase and (right) the newly discovered and more stable fcc phase. Credit: Hugh F. Wilson, et al. ©2013 American Physical Society
bcc = body-centered cubic; fcc = face-centered cubic

(Phys.org) —While everyone is familiar with water in the liquid, ice, and gas phases, water can also exist in many other phases over a vast range of temperature and pressure conditions. One lesser known phase of water is the superionic phase, which is considered an "ice" but exists somewhere between a solid and a liquid: while the oxygen atoms occupy fixed lattice positions as in a solid, the hydrogen atoms migrate through the lattice as in a fluid. Until now, scientists have thought that there was only one phase of superionic ice, but scientists in a new study have discovered a second phase that is more stable than the original. The new phase of superionic ice could make up a large component of the interiors of giant icy planets such as Uranus and Neptune.

The scientists, Hugh F. Wilson (now at the Commonwealth Scientific and Industrial Research Organisation [CSIRO] in Australia), Michael L. Wong, and Burkhard Militzer at the University of California, Berkeley, have published a paper on the new phase of superionic ice in a recent issue of Physical Review Letters.

Phys.org:
New phase of water could dominate the interiors of Uranus and Neptune