Scientists have identified the 19th form of water ice. Strange, four-sided crystals of this rare ice variety, now called Dub Ice XIX, are formed at ultra-low temperatures and ultra-high pressures.
It only exists in laboratory experiments, but researchers say it reveals more about others. Forms of ice, Which can be found in the Earth’s crust and on very cold planets and the moon.
“For the name of the new ice, there is a need to explain exactly what the crystal structure is,” said Thomas Loerting, president of physical chemistry at the University of Innsbruck in Austria. ‘That means finding the simplest iterative structure of a crystal, where all those atoms are located within that structure, and what is the symmetry of the crystalline structure,’ Lourting said.
“If all this is known, then you are only allowed to name your ice … Ice XIX is now the name for the new ice phase discovered in our work,” he said in an email to Live Science.
Lorting and his colleagues published an article in the journal on February 18 describing the new form of ice. Nature Communications, With research conducted by Japanese researchers who tested the discovery.
Related: Snowflake Gallery: No two identical
A new ice
Almost everyone is familiar with the beautiful six-sided variation of snowflakes, which mirror the hexagonal arrangement of oxygen molecules in water ice crystals.
But the regular six-sided crystals of ice – the ice eye – are actually one of its many forms, known as the pym limorph. And until recently, 18 different limorphs of water ice were formally identified – although only six-sided ice is common on Earth. Although ice may seem easy, it is a complex material. For example, only Oxygen The atoms in the water molecules of the six-sided ice crystals form a hexagonal shape, while their hydrogen atoms are randomly oriented around them. In ice terms I call this ice “messy” or “depressed” ice. One of the properties of such irregular ices is that they can be distorted under pressure: “This is the reason why glaciers flow,” Lourting said.
On the contrary, this Hydrogen Atom Many other ice limorphs also have their own crystal patterns and as a result are called “hydrogen-order” or “H-order”. Unlike chaotic ice, H-ordered ices are very brittle and, instead of spoiling, disintegrate, he said.
In those terms, the newly identified 19th form of ice is H-ordered ice; In fact, it is the H-order form of chaotic ice, called ice (VI), which has a random pattern of hydrogen atoms. And Ice HV also has another H-ordered Pymorph, Ice ISV, in which the hydrogen atoms are arranged in a completely different pattern.
“Ice VI, Ice XV and Ice XIX, are all the same in terms of density [because] “It has a single network of oxygen atoms.” Said Lorting. “But it’s different in terms of the position of the hydrogen atoms.” This is the first time such a relationship has been discovered between ice pymorphus, and it may allow experiments. Study transitions between one form and another, he said.
Crystal structure
Lorting’s team created Ice XIX in their laboratory experiments three years ago, subtracting the cooling process of Ice XV to 170 degrees Celsius (minus 274 degrees Fahrenheit) and greatly increasing the pressure to about 2 gigapascals. But the details of its crystalline structure have not been revealed to him until he can study it by a process called neutron diffraction, which can reveal the molecular structure of a material by bouncing the flow of neutrons and examining the resulting dissolution.
Under normal circumstances neutron scattering requires the sample to be filled with water with heavy water that has extra neutrons. Pure heavy water was impractical for the Ice XIX experiments because it freezes more slowly, Lerting said. Progress was to take large amounts of water with a regular fraction of light water, producing water that freezes quickly but allows neutron dispersion.
Lawerting explained that the structure of water ice is the key to the nature of hydrogen bonds, which is incompletely understood. It is also important to understand the ice giants Uranus and the icy moons of Neptune and Jupiter (including Europa, Io and Ganymede), where some other ice pymorphs are found.
“Astrophysics is of great interest in understanding the behavior of icy mantles or icy cores of these celestial bodies, the density of ice phases and its properties.”
And there are still a lot of ice limorphs. The discovery of Ice XIX has produced six ice polymorphs at the University of Innsbruck since the 1980s, and Loerting hopes his team will discover the next one. “The race for Ice Ice XX started yesterday, and I hope my research team will publish it,” he said.
“Published on Original Living Science.
