Scientists Discover New Form of Ice That Forms at Steel-Melting Heat

Researchers at France's CEA created hexagonal close-packed (hcp) superionic ice at pressures up to 219 GPa and temperatures of 2630 K using diamond anvil cells. The phase could exist inside Uranus and Neptune and help explain their non-axisymmetric magnetic fields.

• hcp ice formed at 219 GPa and 2630 K in diamond anvil cells
• At 197 GPa and 2250 K hcp peaks grew as fcc peaks nearly vanished
• Superionic ice was first confirmed experimentally in 2019 as Ice XVIII
• The finding may explain Uranus and Neptune magnetic fields