Discovery of new forms of 'salt ice' may explain mysterious signatures on the surfaces of icy moons

The red streaks that criss-cross the surface of Jupiter's moon are thought to be a frozen mixture of water and salts, but their chemical signature has not matched any material known on Earth so far.

Scientists have discovered two new forms of "salt ice" that form when water and ordinary salt are combined under cold and high pressure conditions.

Created in the laboratory by squeezing salt water between two diamonds, these strange structures can be found on the surfaces and depths of the icy ocean-bearing moons around Jupiter and Saturn.

Besides being important for planetary science, the findings could also have implications for the study of physical chemistry and even energy research. These chemical synapses, known as hydrates (a term used in inorganic and organic chemistry to refer to materials that contain water of crystallization), are used to store energy. .

The author of the paper and planetary scientist Professor Baptiste Journeau of the University of Washington says: "Nowadays there are fundamental discoveries in science. Salt and water are well known in the conditions of the Earth. And now, we have these planetary bodies that may contain compounds that are very familiar to us, but in "Very strange conditions. We have to recover all the basic metallurgy that was done in the 19th century, but at high pressure and low temperature. It's exciting."

Professor Journo explains that water and salts combine in cold temperatures to form a hard, salty network of ice, known as hydrates, which is held together by hydrogen bonds.

Until now, sodium chloride (table salt) was only known to have a single hydrate configuration, which is a relatively simple structure containing one molecule of salt for every two molecules of water.

However, the new hydrate that the researchers discovered under moderate pressures and low temperatures is completely different.

Ground sodium chloride hydrate consists of one salt molecule bonded by hydrogen bonds with two water molecules. In contrast, the hydrate created in the laboratory consists of two molecules of sodium chloride for every 17 water molecules, and the other contains one sodium chloride molecule for every 13 water molecules.

In the study, Professor Journo and his colleagues placed a tiny drop of salt between a pair of diamonds and used them to compress the liquid to 25,000 times the Earth's atmospheric pressure.

Professor Giorneau said: "We were trying to measure how adding salt would change the amount of ice we could get, because salt acts as an anti-freeze. Surprisingly, when we did the pressure, what we saw was that these crystals, which we weren't expecting, started to grow. It was a very surprising discovery."

Furthermore, he noted, the crystals "have the structure that planetary scientists were expecting."

The chemical signatures from the surface of Jupiter's moon appear more "hydrous" than expected, a fact that can be explained by the different water-to-ice ratios found in the high-pressure hydrates discovered by Professor Guru and his team.

In fact, according to the scientists, the kinds of cold, high-pressure conditions they replicated in their diamond press would be common on the Jovian moons, where ice crusts three to six miles thick, scientists believe, hide oceans up to several hundred miles wide. Even denser forms of ice may lie at the bottom of these oceans.

Professor Journo explained: "Pressure brings the molecules closer together, so their interaction changes, and this is the main driver of the diversity in the crystal structures that we found."

The team found that one of these hydrates remained stable even after the pressure applied to the diamond piston was released.

Professor Journeau said: "We've determined that it should remain stable at standard pressure up to about -50 degrees Celsius (-58 degrees Fahrenheit). So if you have a very saline lake, for example in Antarctica, you can be exposed to these temperatures. This newly discovered hydrate may be out there."

With their initial study complete, the scientists are now looking to either produce or collect larger samples of the new hydrate.

This will allow them to analyze the chemical structures in more detail, and determine if their signatures match those detected from Jupiter's icy moons.

Source: Express