Scientists have created exotic forms of ice never seen on Earth

Ice has many forms besides the common substance produced in a normal freezer.

It is likely that all of your encounters with frozen water, from trudging through winter streets covered in melting snow, to sipping fresh lemonades in summer, have been limited to a single structural form of ice, called “Ih,” where oh refers to the hexagonal nature of your crystalline network.

But the ice is much more than thatnote to .

For more than a century, scientists have been striving to subject ice to extreme conditionscreating progressively more exotic structures — in fact, they have produced more than 20 crystalline forms to date, none of which we are likely to experience in our lifetimes.

“Water is a beautiful, elegant system that consistently exhibits new and remarkable behaviors,” he says. Ashkan Salamatphysical chemist at the University of Nevada, Las Vegas. “For something so simple, there is a admirable complexity“.

At the heart of all these exotic icesas well as our most common ice, water and steam, is the same molecule: H₂Oan oxygen atom flanked by hydrogen atoms that form an angle of 104.5 degrees.

In all varieties of ice, H₂O molecules interact, with weak bonds called hydrogen bondswhich form between an oxygen atom and a hydrogen atom of separate molecules.

Different arrangements of these hydrogen bonds can shape the crystalline structure of ice into various configurations, from a hexagonal prism to a cubic lattice to less familiar lattice systems such as rhombohedral and the tetragonal.

Hydrogen bonds between water molecules are extremely sensitive to temperature and pressure changessays Salamat, giving water what he calls a “near-quantum behavior“.

The molecules are forced to establish dramatically different relationships with each other at certain thresholds of these conditions.

In their ardent search for new forms of ice, Salamat and other scientists create exotic recipes — e.g. crushing water with 3000 times atmospheric pressure, or cooling it with a pinch of potassium hydroxideup to -200°C for a week.

The most recent discovery by these “ice explorers” is the ice XXI, which was presented in an October publication in the magazine Nature Materials by a team of researchers led by physicist Geun Woo Leefrom the University of Science and Technology (UST), in South Korea.

Salamat was not involved in this work, but his team in 2022 at the magazine Physical Review B the discovery of a new transition phase designated VIIt.

Ice XXI is a ephemeral and compact crystalline structure that develops from super-compressed water: scientists have only been able to observe it using a X-ray free electron laser extremely powerful that essentially works as a high speed camera.

“Observe phenomena at a very, very high speed allows us to observe strange and wonderful phenomena“, says Salamat, who calls the laser “a incredibly exciting new toy“.

The laser allows researchers detect exotic ice that exist only briefly, introducing time as a variable along with temperature and pressure.

Although they don’t exist naturally on Earth, some of these strange forms of ice can form in other worlds — deep within Neptune, trapped inside a distant moon or somewhere even more alien.

More, for Thank you, the laboratory may prove equally exotic. “There are still new and exciting things we can discover,” he says.