The researchers have discovered a new form of ice as water can change in phases to different forms with pressure and temperatures.
Now theoretically discovered by researchers from Okayama University in Japan a new family of ice phases known as aeroices lowest density of all known ice crystals. The effects of extreme negative pressure on water molecules investigating a region of negative pressure through molecular dynamic simulations.
Our research, which surveys an entire negative-pressure region for the first time. Exploring vast complicated on the phase diagram said Masakazu Matsumoto, associate professor at the Research Institute for Interdisciplinary Science at Okayama University and a co-author of the paper.
Ices with lower density than normal ice found in many kinds. The understanding of the fundamental properties. Behavior of water in nano tubes and other nano pores, as well as in biomolecules. Seventeen ice phases found experimentally each one numbered in the order two ices have lower density than normal ice.
The molecules of the ice form zeolite structure where guest molecules or atoms are trapped inside. The guest molecules removed resulting in a stable ultra low density ice at high negative pressures. Using a similar technique, another group of researchers discovered ice XVII in 2016.
Researchers studied the possible ice phases still left to explore in the negative pressure region. The structure of silica (SiO2) and ice are common. So, retrieved 200 silica zeolites from the Zeolite Database administered through the International Zeolite Association.
More than 300 structures evaluated. The atoms in the SiO2 structure re arranged removing the two oxygen atoms. Replacing the silicon atom in each molecule with one oxygen atom. The hydrogen atoms added so that the structure obeyed the ice rule. In the density range that is only around half that of liquid water (~0.5 g/cm^3). The researchers showed ice phase is more stable than any zeolite ice.
The researchers made less dense ice structures between 0 and 0.5 grams per cubic centimeter by adding polyhedral building blocks to the zeolitic frameworks to make the structure sparser while satisfying the structural rule for ice.