Scientists have identified the 19th form of water ice. The exotic, four-sided crystals of this rare ice variety, now dubbed ice XIX, form at ultra-low temperatures and ultra-high pressures.
It only exists in laboratory experiments, but researchers say it reveals more about other forms of ice, which can be found deep in the Earth’s mantle and on very cold planets and moons.
“To name a new ice form, one needs to elucidate exactly what the crystal structure is,” said lead researcher Thomas Loerting, a professor of physical chemistry at the University of Innsbruck in Austria. That means figuring out the simplest repeating structure of the crystal, where all of the atoms are located within that structure, and what the symmetry of the crystal structure is, Loerting said.
“Only if all of these are known, you are allowed to name your ice … Ice XIX is now the name for the new ice phase discovered in our work,” he told Live Science in an email.