Can water turn into a metal?

Figure 1: A thin layer of water turned shiny for a few seconds

Source Credit: Nature

We all know that the water we encounter everyday is not a pure substance. In fact, due to the impurities it contains, water can become metallic, or electronically conductive; salts can dissolve into ions that allow unfiltered water to conduct electricity. Therefore, the opposite case is true for pure, filtered water– electrons cannot move freely when there are only water molecules.

However, there is a way to force pure water into a metallic substance: using high pressure. As a matter of fact, in theory, this method has to work in most materials. In metals such as copper and iron, outer electrons can flow and conduct electricity when atoms or molecules are squeezed together tightly enough. Thus, when pressure is applied to water, the free movement of electrons turns it into a metallic state, but applying pressure is not as easy as it sounds.

Water requires 15 million atmospheres of pressure, which is equivalent to 48 times the atmospheric pressure at sea level, in order to become metallic. This level of pressure is possible in laboratory settings, but does not provide an environment to study its metallic state. As a result, an organic chemist Pavel Jungwirth of the Czech Academy of Sciences in Czechia and his team have recently found a new alternative: using alkali metals. Alkali metals, which occupy the first column of the periodic table, only hold one electron in their valence shells. These metals, such as sodium and potassium, become more stable by releasing their electrons; by using this property, water can borrow their electrons and become conductive without high pressure. Last year, a similar effect was observed when tested with ammonia and alkali metals by Jungwirth and another chemist Phil Mason. However, there was still another problem to solve: water and alkali metals are highly reactive, even to the stage of explosion.

As a solution to this challenge, scientists came up with a creative idea: adding water to metal. Instead of dropping metal into water, which would definitely result in an explosion, the team decided to use vapor deposition to add a thin layer of water onto an alloy of sodium-potassium in a liquid state. A more detailed procedure includes putting a syringe filled with sodium and potassium inside a vacuum chamber and exposing droplets to water vapor. During the experiment, the water condensed to the surface into a layer one-tenth of a micrometer thick, and the electrons from the combined metal quickly moved into the water. That moment, scientists observed a golden shine.

Water becoming metallic was thought to have been only possible at the centers of other massive planets, such as Neptune or Uranus. Especially because the high pressure seemed to be nearly impossible to perform on water with current technology, scientists found this particular discovery with great excitement. The journey was definitely not easy; in addition to using alkali metals, they had to be cautious so that electrons can diffuse into water before chemical decomposition. Overcoming these obstacles, Jungwirth commented, “it was amazing, like [when] you discover a new element.”

Q&A:

Hannah: How is this metallic water useful? Is it better than other materials in certain aspects (i.e. durability, accessibility, cost, etc)?

• The scientists highlight the significance of producing metallic water on Earth instead of comparing it with other materials. Therefore, at this stage, I believe it is too early to put emphasis on its superior properties.

Wooseok: Are there any health implications when people are exposed to this new type of water for long periods of time?

• Health concerns are not revealed yet. However, there might be a risk during the process of turning water into a metallic state due to the danger of explosion.

Jennah: Could you explain why this method should theoretically work in most elements?

• As “Water Transformed into Shiny, Golden Metal” mentioned, “Atoms or molecules can be squeezed together so tightly that they begin to share their outer electrons, which can then travel and conduct electricity as they do in a chunk of copper or iron.”

John: What properties of water makes it give off a golden sheen when it becomes metallic?

• It is not just water that gives off a golden sheen. Researchers discussed their previous experiment with ammonia, which also turned shiny. Therefore, it does not depend on water’s properties, but rather because metals have shiny appearances.

Xavier: Was the idea to force water into a metallic state studied prior to Jungwirth’s recent research, or something that was never attempted before?

• Jungwirth was one of the first scientists who used the new method, adding water to the metal, to force water into a metallic state. However, it is uncertain whether the idea itself has originated from him.

Fabian:What differentiates Uranus or Neptune from Earth, in terms of elements or atmosphere, that allows the two planets to form metals?

• Uranus and Neptune are giant planets that have extremely high pressures at their cores. Thus, as explained above in the article, water may be in a metallic state on these planets.

Works Cited:

Castelvecchi, Davide. “Water Transformed into Shiny, Golden Metal.” Nature News, Nature Publishing Group, 28 July 2021, www.nature.com/articles/d41586-021-02065-w.

Lanese, Nicoletta. “Scientists Transform Water into Shiny, Golden Metal.” LiveScience, Purch, 30 July 2021, www.livescience.com/water-into-metal-experiment.html.

Starr, Michelle. “Scientists Have Transformed Pure Water Into a Metal.” ScienceAlert, www.sciencealert.com/scientists-have-found-a-new-way-to-turn-water-metallic.