“Ice XXI” is an entirely new phase of ice with a crystal structure that’s more complex than the ice found on Titan or Ganymede.
For something so common to our daily lives, there’s a surprisingly long list of questions scientists have yet to answer about ice—the solid form of water, seen in iced coffee, the frosty sprinkle on mountaintops, and, of course, extraterrestrial surfaces. Fascinatingly, scientists keep finding entirely new types of ice, adding to the mystery surrounding how ice forms in different environments.
In a recent Nature Materials paper, a team of scientists led by the Korea Research Institute of Standards and Science (KRISS) reported the discovery of ice XXI, an entirely new phase of ice that forms when water is rapidly compressed at room temperature. What’s particularly intriguing about this ice form is that it emerges within the pressure range of ice VI—a previously known form of ice thought to exist inside icy moons such as Titan and Ganymede.Icy pathways
Chemically speaking, water—despite containing two elements, hydrogen and oxygen—can form a remarkably diverse range of crystalline structures as a solid. So far, scientists have discovered 20 different arrangements of pure ice; as the Roman numeral indicates, ice XXI is the 21st.
