Scientists Find New Form Of Ice With Record-Low Density
An amazing form of frozen water, with a record-low density at merely 25 percent has been made by a team of researchers from the University of Nebraska - Lincoln.
It has broken an earlier record set by a team of European scientists two years ago. Synthesising the current ice will highlight the 18th known crystalline form of water, discovered in the U.S. after World War II.
"We performed a lot of calculations (focused on) whether this is not just a low-density ice, but perhaps the lowest-density ice to date," Xiao Cheng Zeng, co-author of the study, said in a press release. "A lot of people are interested in predicting a new ice structure beyond the state of the art."
A computational algorithm and molecular simulation was used to locate the extreme pressure and temperature ranges that would permit the freezing of water into their hypotheticated configurations that take the form of a clathrate. This is a series of water molecules interlocking each other like a cage.
Earlier, scientists said that "guest molecules" were required in these cages so that their structural integrity can be maintained. However, the clathrate was perceived to remain stable even after the removal of the molecules.
The prediction is that the new ice will only form when the water molecules are kept within a closed space, put under high, "outwardly expanding pressure".
"Water and ice are forever interesting because they have such relevance to human beings and life," Zeng said. "If you think about it, the low density of natural ice protects the water below it; if it were denser, water would freeze from the bottom up, and no living species could survive. So Mother Nature's combination is just so perfect."
The study was published in Feb. 12,2016 issue of Science Advances.