Pure water can serve as an insulator that is almost perfect. Researchers were also able to demonstrate how this fluid can be converted into metal.
How Pure Water Becomes Electronically Conductive Metal
Water that can be found in nature is able to conduct electricity. However, this is due to the impurities that dissolve and become free ions that enable the flow of electric current. Pure water only turns metallic or electronically conductive at pressures that are extremely high and that exceed what can be lab-produced.
However, researchers were able to show that high pressure is not the only one that can lead to pure water metallicity. They demonstrated it through the "Spectroscopic evidence for a gold-coloured metallic water solution" study.
By making pure water come into contact with an alkali metal that shares electrons, charged and free-moving particles can be added. This, thus, makes water metallic. In this case, the alkali metal used was a potassium and sodium alloy.
The conductivity that results only lasts for a couple of seconds. However, it is a crucial step towards the capacity to understand this water phase by direct study.
Physicist Rober Seidel, who is from Germany's Helmholtz-Zentrum Berlin für Materialien und Energie, explained that the transition to become metallic water could be seen with the naked eye. Seidel notes that the silvery droplet of sodium and potassium coats itself with an impressive golden glow.
Making Material Electronically Conductive
In theory, any material could become conductive under pressure levels that are high enough. The notion is that if atoms are tightly squeezed enough, the outer electrons' orbitals would begin overlapping. This would enable them to move around. For water, the pressure reaches roughly 48 megabars, which is just below 48 million times the atmospheric pressure of the Earth's sea level.
Though pressures that go beyond these levels were generated in a lab setup, these experiments are not suitable for the study of metallic water. Hence, the team decided to utilize alkali metals, which easily release outer electrons. This means that in the absence of high pressures, they are capable of inducing the properties of electron-sharing of pure water that is highly pressurized.
However, this is one issue with this approach. The reactivity of alkali metals with liquid water is high. This could even reach the point of being explosive.
The researchers were able to address this issue. Within a vacuum chamber, the researchers began extruding from a small sodium-potassium alloy blob's nozzle. They carefully added a thin, pure water film through vapor deposition. When they got into contact, the positively charged ions as well as the electrons flowed from the alloy into the water.
This didn't just give the water a golden hue. It also made the water conductive, similar to what can be observed in metallic water that is highly pressurized. This was also confirmed through synchrotron X-ray photoelectron spectroscopy and optical reflection spectroscopy.
Both properties, the conductive band and the golden sheen, took up different ranges of frequency. This allowed them to be clearly identified.
Seidel explains that the study does not just show that metallic water can be produced within the Earth but also characterizes the spectroscopic characteristics linked to its golden luster.
While the findings could offer more understanding regarding phase transition within the planet, the researchers may also allow in-depth study of large planets' conditions of extreme pressure.
Check out more news and information on Physics & Math in Science Times.
