Until now, it was assumed that it would not be possible to prepare water with a conduction band typical of metal under terrestrial conditions in the foreseeable future, because under terrestrial conditions it would not be possible to reach the pressure that would allow it.
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Clean water practically does not conduct electricity. For example, in order to conduct electricity, it must contain dissolved salts. However, the conductivity of such an electrolyte is relatively low, compared to metals it is lower by several orders of magnitude.
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Scientists speculate that water can be as conductive as copper wire, for example, in the cores of large planets, where high pressure presses water molecules together to begin to overlap their electron shells. This creates a conductivity band typical of metallic materials. Under terrestrial conditions, such pressure cannot be achieved, but Jungwirth’s team used a procedure that does not need it to prepare metallic water.
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They tested the method of massive dissolution of alkali metal electrons in water. An explosion will occur after the normal addition of sodium to water, for example.
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“Among the favorite school experiments and themes of many videos on youtube is throwing sodium into the water. As is notoriously known, when a piece of sodium is thrown into water, metal water is not formed, but a massive explosion immediately destroys the apparatus, “Jungwirth remarked. “In order to tame this intensive chemistry, which is not very useful for laboratory purposes, we went for it from the other side. We did not add alkali metal to the water, but water to the metal, “the scientist explained
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Researchers described the transition to “metallic behavior” at the molecular level last spring, and an article about their discovery was published in the journal Science. “It was such a preparatory job that we tested it on liquid ammonia. Such an exercise for real. And the (metal) water is real, “Jungwirth told ČTK.
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He pointed out that the team “played” with the explosions. “By understanding how the explosions work, we came up with a way around it,” said the scientist.
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The first image shows a pure drop of sodium-potassium alloy, in the others the drop is exposed to water vapor. A layer of water settles on it, in which the electrons released from the metal dissolve, giving it a golden metallic luster.
Photo: IOCB AS CR / Jana Plavec
A successful method is that in a vacuum chamber, scientists exposed a drop of an alloy of sodium and potassium to a small amount of water vapor, which began to condense on its surface. In this way, the electrons released from the alkali metal dissolved into the water layer faster than the chemical reaction causing the explosion. There were enough of them to cross the line to create a conduction belt. An aqueous metal solution was formed which contained both these electrons and dissolved alkaline cations and chemically formed hydroxide and hydrogen.
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“Thanks to that, we managed to create a thin layer of a gold-colored metallic aqueous solution for a few seconds. That was enough for us to not only see it with our own eyes, but also measure the spectrometers, “said Jungwirth.
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“At the same time, we made the necessary equipment more or less on our knees in a small laboratory in our Prague institute, where the first experiments also took place. We then obtained key evidence for the presence of metallic water using X-ray photoelectron spectroscopy on a synchrotron in Berlin, “the scientist added.
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The team thus achieved a goal that Jungwirth had previously described as “the most explosive dream”. “Of course, there are still many things to do. When we did it on the ammonia, we were able to map the transition from when it is metal, when it is no longer metal. From that gold color to blue. Something similar could go in the water. And I think it will work, “said Jungwirth. He has now described the act as “nice basic research” that brings new knowledge and can attract students to chemistry.
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