Ice is something we are all too familiar with, water freezes into ice when its temperature drops below 0°C. But are you really familiar with ice? Did you know that scientists have discovered 19 types of ice so far?
Ice’s “Fellow” Brother
You read that right, there are indeed 19 types of ice on the earth. In February 2021, Thomas Lorting, a physical chemist at the University of Innsbruck in Austria, said that his team produced the 19th type of ice on earth. Ice – Ice XI X. You must be very surprised. Isn’t the ice we usually see all transparent and colorless solids? How are they divided into 19 types?
On the earth’s surface, the atmospheric pressure is 1.0 × 103 Pa (one standard atmosphere), and under this pressure, water freezes at 0°C. But we know that as the pressure increases, the boiling point of the object will increase, and similarly, the freezing point of the object will also increase, and the atomic ordering inside the object will also change, which will affect the physical and chemical properties of the object. At this time, we It can be considered that a new substance has been produced.
Ice I is the kind of ice that can be found everywhere on Earth. The oxygen atoms are arranged in hexagons, and the hydrogen atoms are randomly oriented in different spatial directions. There is no definite ordering between the atoms, so ice I can deform when the pressure changes. , which is why glaciers flow. But in ice that freezes at other pressures and temperatures, the arrangement of oxygen atoms changes, from boxy to cage-like, and so on. In this way, the spacing between the hydrogen and oxygen atoms will change. When the spacing is narrowed, it will force the hydrogen atoms between the oxygen atoms to form a fixed order. This ordered ice is very brittle and will break when the pressure changes. cracked rather than deformed. In addition, due to the change in atomic spacing, the interatomic forces will also change, these atoms are no longer as “indifferent” as the hydrogen and oxygen atoms in Ice I, and they may interact with other object atoms, resulting in unexpected effect.
In 1900, German physical chemist Gustav Taman put forward the idea that freezing water at different pressures and temperatures can produce different ices, and using a high pressure of 200 MPa and -70 ℃ ~ -80 The temperature of ℃ produced the second kind of ice in the world – ice II in which the oxygen atoms are arranged in cubes. Later generations created Ice III, Ice IV… until Ice XVIII by further adjusting the temperature and pressure.
When physicists created Ice XV, they discovered that it had a different relationship with Ice VI than other ice brothers: they were closer “twin brothers.” Ice XV and Ice VI have very similar densities because they share the same structural network of oxygen atoms, except that the hydrogen atoms are arranged in a different order. This means that the two ice forms can be converted into each other by simply changing the pressure and temperature conditions. This pattern was used by Lortin’s team to create Ice XIX: by cooling Ice XV to -170°C and increasing the pressure dramatically to 2 gigapascals. Conversely, heating ice XIX at atmospheric pressure yields ice XV and ice VI. This is another way to make ice brothers, and apparently this method can be used to discover or create new types of ice more efficiently.
“Ice Brothers” Widely Existed on Alien Planets
”Ice brothers” widely exist on alien planets and are about to melt, and have no practical effect. Why do scientists spend so much effort to make these ices?
Although only one type of natural ice exists on the earth’s surface, other types of ice may exist widely in the depths of the earth and on other planets in the universe. Ice deep in the Earth can combine with other matter into new states, and understanding these states could help solve some long-standing puzzles. The existence of ice in alien planets not only explains some previously unknown planetary mysteries, but also proves that there may be water in alien planets, and water is an essential substance for the origin of life. That’s exactly what it means to know the type of ice.
On January 24, 1986, the American interstellar probe “Voyager 2” arrived near Uranus and detected some basic conditions of Uranus. In the data returned by Voyager 2, the researchers found a puzzling phenomenon. There are some planets in the solar system that have magnetic fields like the earth. These magnetic fields are similar to the geomagnetic field, with clear north and south poles. According to the data returned by Voyager 2, Uranus’s magnetic field is extremely complex, not only the north and south poles. , it has multiple magnetic poles, and the flow direction of the magnetic field lines is not consistent with its rotation direction. Uranus is not an exception, the same phenomenon occurs with Neptune.
The reason why the geomagnetic field has clear poles is that the liquid iron in the earth’s core flows regularly, generating a current with a fixed direction, so the direction of the geomagnetic field is basically stable. The magnetic field directions of Uranus and Neptune are so chaotic that they can only be explained by the fact that there is no “dynamo” running regularly in the core, and its electric field and current exist in every corner of the outer shell, so the directions of the magnetic field lines are different. To support this explanation, in 1988, scientists predicted that in the interiors of Uranus and Neptune, due to extreme pressure and extreme temperatures, water would freeze into a new type of ice – ice XVIII, which is a type of ice that can conduct electricity, so Electric and magnetic fields in various directions are generated.
It was not until May 2019 that this conjecture was confirmed: scientists at the Lawrence Livermore National Laboratory in the United States successfully created ice XVIII with the help of high-energy lasers and X-rays. On the table in the laboratory, there are two diamonds facing each other with a thin layer of water sandwiched between them. When the scientist pressed the button of the laser, six huge laser beams generated a series of shock waves of increasing intensity, instantly giving the thin layer of liquid water a pressure equivalent to 4 million times atmospheric pressure and heating it to a high temperature of up to 2760°C , a new type of oxygen cube ice is formed, which is Ice XVIII.
Although the ice XVIII melted quickly, X-rays scanned the ice XVIII in an instant, recording its atomic structure. According to the data obtained by X-rays, in ice XVIII, the oxygen atoms are trapped in a cubic lattice, and the distance between the atoms is very close, so some hydrogen atoms can move between adjacent water molecules, because of the high speed, as if in the Flow in general. In the process of flowing, the electrons failed to catch up with the protons and were abandoned in place. In the end, it was actually the positively charged protons that participated in the flow. In this way, an electric current was generated in the ice XVIII, which is also the ability of the ice XVIII to conduct electricity. reason. In the interior of Uranus and Neptune, it may be the “mantle” composed of ice XVIII, which has a peculiar electrical conductivity, thus prompting the two planets to generate different magnetic fields.
“Ice Brothers” Deep in the Earth’s Crust
Not only alien planets, there are also some different “ice brothers” deep in the earth, which constitute “cages” that bind certain substances. In 2014, scientists at the University of Göttingen in Germany found naturally occurring ice XVI in neon gas hydrates. Gas hydrates are cage-like crystals of ice in which foreign gas molecules are firmly surrounded by a crystalline network formed by hydrogen bonding of water molecules. The researchers extracted the neon gas from the neon gas hydrate, leaving only the crystal structure formed by water molecules. This is ice XVI, which is the least dense form of ice crystals, so it can trap the neon gas with very little mass. .
In addition to neon gas hydrates, other types of gas hydrates exist deep in the Earth’s crust, such as methane hydrates (i.e. flammable ice) that are abundant in permafrost and seabeds. Some scientists have envisioned that if methane from combustible ice could be released for energy use, while carbon dioxide was fixed in gas hydrates, it could both capture energy and reduce greenhouse gases in the atmosphere. Finding an “ice brother” who can fulfill this important task may be able to realize this vision.
In addition, in the process of oil and natural gas transportation, the special pressure and temperature environment can easily cause some gas and water to form gas hydrate, thereby blocking the pipeline. The researchers believe that a better understanding of gas hydrates could also help address this question.
19 ice brothers with very different “personalities” may be found in all corners of the universe, playing different roles. What surprises will ice cubes give us in the future?