Researchers have created metallic water for the first time. Through a very careful experimental setup, the team grew a thin layer of a gold-colored metallic water on the outside of a droplet of liquid metal.
It may be surprising for most people to find out that water is actually an insulator – at least when it’s perfectly pure. The stuff that comes out of the tap, however, is a well-known conductor of electricity, due to the salts and impurities it contains. But making pure water metallic, or conductive, has long been a scientific challenge.
But now, a team of researchers from 11 institutions around the world has pulled it off at the BESSY II facility in Berlin. The key to the breakthrough was to pair the water with an alkali metal, which are known to easily release electrons from the outer shells of their atoms.
The problem is, water and alkali metals famously don’t mix well – the metals can fizz, ignite, and even explode when dropped into water. So for this experiment the researchers inverted the usual mix, coating alkali metal in a thin layer of water.
Inside a vacuum chamber, a sodium-potassium (Na-K) alloy – which exists as a liquid at room temperature – was dripped from a nozzle. Water vapor was then piped into the chamber, forming an extremely thin skin on the outside of the metal droplet. Electrons and metal cations then flow from the Na-K into the water, creating conductive metallic water.
"You can see the phase transition to metallic water with the naked eye!” says Dr. Robert Seidel, an author of the study. “The silvery sodium-potassium droplet covers itself with a golden glow, which is very impressive.”
To investigate what was happening, the scientists examined the short-lived metallic water using optical reflection spectroscopy and synchrotron X-ray photoelectron spectroscopy. This confirmed the metallic phase.
"Our study not only shows that metallic water can indeed be produced on Earth, but also characterizes the spectroscopic properties associated with its beautiful golden metallic luster," says Seidel.
The research was published in the journal Nature.
Source: Helmholtz Zentrum Berlin