Morales, M. A., Hamel, S., Caspersen, K. & Schwegler, E. Hydrogen - helium demixing from first principles:
from diamond anvil cells to planetary interiors.
Using
diamond anvil cells (DAC), the team applied 2.5 GPa of pressure (25 thousand atmospheres) to pre-compress water into the room - temperature ice VII, a cubic crystalline form that is different
from «ice - cube» hexagonal ice, in addition to being 60 percent denser than water at ambient pressure and temperature.