This new form of frozen water could have the lowest density for ice ever discovered.
The proposed ice – whose molecular form was calculated by a University of Nebraska Lincoln-led team of researchers – has a record-low density of 25 percent less than the one synthesized by European scientists back in 2014.
If this proposed ice can be synthesized, it would be the 18th of known crystalline forms of water, as well as the first to be discovered in the U.S. since before the World War II.
According to study author and chemistry professor Xiao Cheng Zeng, they made a lot of calculations to determine if it is the lowest-dense ice at present.
"A lot of people are interested in predicting a new ice structure beyond the state of the art,” says Zeng, who earlier discovered a 2D “Nebraska Ice” that contracts instead of expands when frozen under specific settings.
A computational algorithm as well as molecular simulation helped the team predict the new frozen-water form, which will be called “Ice XVII.” The said configuration appears to be a kind of clathrate, a series of water molecules forming an interlocking and cage-like foundation.
While it has been long established that those clathrates structures can only keep their integrity when containing a so-called “guest molecule” such as methane, the researchers are calculating if these cages would hold together despite a guest molecular exiting the environment.
It won’t be an easy process to synthesize this new form of ice, as it is only predicted to form when water molecules are put inside an enclosure subjected to extremely high and outwardly expanding pressure.
The temperature is another critical factor. At -10 degrees Fahrenheit, warned the researchers, the pressure level necessary for producing the ice would be four times greater than that of the deepest trench of the Pacific Ocean. At -460 degrees F, it would be even greater, or about the same amount one would feel while trapped underneath 300 jumbo jets at sea level.
The ice could then be synthesized through vacuuming guest molecules out.
Zeng’s team is inspired by the mere wonders of ordinary ice, which has covered the planet for billions of years.
"Water and ice are forever interesting because they have such relevance to human beings and life,” he says. The low density of ice ably protects the water beneath it – anything denser would freeze the water from the bottom up and hinder life from flourishing, he cited as an example.
The findings were discussed in the journal Science Advances.
