Scientists using the Advanced Photon Source have recreated ‘superionic ice’, the kind formed at the center of our ice giants Uranus and Neptune. We all know that there are three forms of matter: liquid, solid, and gas. It turns out, though, that under different conditions, water can form more than a dozen different structures. Superionic ice forms under extreme pressures and temperatures, such as in the center of ice giants. And while scientists had previously managed to create the substance once before, it was only for an instant. Now, they have managed to create, sustain, and even examine the ice.

The team pressed their sample between two diamonds and then used lasers to heat the sample up. Once that was underway, they used X-ray beams to measure how the X-rays scattered off the interior structure, and that’s how they mapped out just what superionic ice is. At first, the measurements were confusing. As co-author Vitali Prakapenka noted: …when I turned off the laser and the sample returned to room temperature, the ice went back to its original state. That means it was a reversible, structural change, not a chemical reaction.

So just what is this structure? Prakapenka explains: Imagine a cube, a lattice with oxygen atoms at the corners connected by hydrogen. When it transforms into this new superionic phase, the lattice expands, allowing the hydrogen atoms to migrate around while the oxygen atoms remain steady in their positions. It’s kind of like a solid oxygen lattice sitting in an ocean of floating hydrogen atoms.

This work was published in the journal Nature Physics. There is still a lot to learn about this new form of ice, and we will bring it to you here on the Daily Space.

More Information

Argonne National Laboratory press release

“Structure and properties of two superionic ice phases,” Vitali B. Prakapenka, Nicholas Holtgrewe, Sergey S. Lobanov and Alexander F. Goncharov, 2021 October 14, Nature Physics