(ORDO NEWS) — Right at the molecular level, water ice can form from a wide variety of structures. While they are all fairly similar in appearance, their differences in properties mean that different solidified H 2 O structures can react and behave differently.
One of these phases is called cubic. ice, and this is the subject of ongoing scientific debate.
In fact, some researchers are even wondering if it actually exists. Ice previously described as mostly cubic may actually be a mixture containing other, more common types of ice.
In a new study, scientists from the Chinese Academy of Sciences (CAS) and other institutions claim to create fairly pure cubic ice or Ice Ic, to use its technical term.
“There is the longstanding debate about whether water can freeze to form cubic ice a currently undescribed phase in phase space. ordinary hexagonal ice,” the researchers write in a published article.
The phase of ice is determined by environmental conditions, such as temperature and pressure, which affect its formation. In cubic ice, water molecules and ice crystals are arranged in a cubic fashion, hence the name.
Using a technique known as transmission electron microscopy (TEM), the team examined the formation of ice on two-dimensional sheets of carbon. called graphene at very low temperatures.
TEM uses electron beams and their reactions to image objects at the molecular scale.
The ice that formed was mostly cubic ice, with a smaller amount of more regular hexagonal ice (Ih Ih) next to it.
The scientists say the formation of two ice phases may give scientists insight into why cubic ice hasn’t manifested properly in past experiments.
“The observed pure-phase single crystals fully demonstrate the heterogeneous nucleation of pure-phase ice Ic under the current condition,” the researchers wrote.
There were no transitions between cubic and hexagonal ice, the team says, and cubic ice remained stable under the experimental conditions; 102 Kelvin (-171 degrees Celsius or -276 degrees Fahrenheit).
This stability has been a problem in the past.
As this experiment shows, cubic ice is more likely to form at very low temperatures, well below what you would get in a home freezer.
This means that understanding is important for studying ice in the upper atmosphere, ice used for cryopreservation, and so on.
The case has not yet been closed, and the researchers acknowledge that further research is needed. to confirm the existence and properties of cubic ice, including how its defects can affect its behavior.
“Studying the structure and dynamics of defects in ice Ic provides a key step towards understanding ice plasticity at the molecular level,” the researchers wrote.
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