Search for the distorted counterpart of ice XV and hydrogen-ordered ice IV

Water ice displays a remarkably complex phase diagram. The last five years have seen rapid developments in this area of research with the discovery of three new phases of ice. Our team has been involved in the discovery of ice XIX and shown that ice XIX is a distorted version of the well-known ice VI. The type of distortion observed during the ice VI to ice XIX phase transition is similar to the ones observed for perovskites under pressure and we will now investigate if such distortions are also possible for ice XV, the hydrogen-ordered counter part of ice VI. Additionally, we will also search for the so far unidentified hydrogen-ordered counterpart of ice IV. In summary, these experiments may lead to the discovery of two new phases of ice. In any case, we will gain new and highly valuable insights into the low-temperature / high-pressure behaviour of ice.