SLAC scientists created gold hydride in excessive lab situations. The work sheds gentle on dense hydrogen and fusion processes.
By probability and for the primary time, a global crew of researchers led by scientists on the U.S. Division of Power’s SLAC Nationwide Accelerator Laboratory succeeded in creating strong binary gold hydride—a compound composed solely of gold and hydrogen atoms.
The crew had initially got down to examine how hydrocarbons, molecules manufactured from carbon and hydrogen, rework into diamonds underneath excessive stress and warmth. Throughout experiments on the European XFEL (X-ray Free-Electron Laser) in Germany, they positioned hydrocarbon samples with a skinny layer of gold foil, supposed solely to soak up X-rays and switch warmth to the comparatively weakly absorbing hydrocarbons. Unexpectedly, alongside diamond formation, they noticed the creation of gold hydride.
“It was surprising as a result of gold is usually chemically very boring and unreactive – that’s why we use it as an X-ray absorber in these experiments,” defined Mungo Frost, a workers scientist at SLAC and the examine’s lead creator. “These outcomes recommend there’s probably plenty of new chemistry to be found at excessive situations the place the consequences of temperature and stress begin competing with standard chemistry, and you’ll kind these unique compounds.”
The findings, revealed in Angewandte Chemie Worldwide Version, display how chemical conduct can shift dramatically underneath excessive environments, resembling these discovered deep inside planets or inside hydrogen-fusing stars.
Learning dense hydrogen
To attain these outcomes, the researchers compressed hydrocarbon samples to pressures exceeding these inside Earth’s mantle utilizing a diamond anvil cell. They then uncovered the samples to bursts of X-ray pulses from the European XFEL, heating them above 3,500 levels Fahrenheit. By analyzing how the X-rays scattered from the samples, the team tracked the structural changes taking place.
As anticipated, the data confirmed that carbon atoms had arranged into a diamond lattice. However, they also revealed unexpected signals: hydrogen atoms had reacted with the gold foil to form gold hydride.
At the conditions generated in the experiment, hydrogen existed in a dense, “superionic” state, in which hydrogen atoms moved freely within the rigid gold lattice. This behavior enhanced the conductivity of the gold hydride, offering new insight into the behavior of materials under extreme pressures and temperatures.
Hydrogen, which is the lightest element of the periodic table, is tricky to study with X-rays because it scatters X-rays only weakly. Here, however, the superionic hydrogen interacted with the much heavier gold atoms, and the team was able to observe hydrogen’s impact on how the gold lattice scattered X-rays. “We can use the gold lattice as a witness for what the hydrogen is doing,” Mungo said.
The gold hydride offers a way to study dense atomic hydrogen under conditions that might also apply to other situations that are experimentally not directly accessible. For example, dense hydrogen makes up the interiors of certain planets, so studying it in the lab could teach us more about those foreign worlds. It could also provide new insights into nuclear fusion processes inside stars like our sun and help develop technology to harness fusion energy here on Earth.
Exploring new chemistry
In addition to paving the way for studies of dense hydrogen, the research also offers an avenue for exploring new chemistry. Gold, which is commonly regarded as an unreactive metal, was found to form a stable hydride at extremely high pressure and temperature. In fact, it appears to be only stable at those extreme conditions as when it cools down, the gold and hydrogen separate. The simulations also showed that more hydrogen could fit in the gold lattice at higher pressure.
The simulation framework could also be extended beyond gold hydride. “It’s important that we can experimentally produce and model these states under these extreme conditions,” said Siegfried Glenzer, High Energy Density Division director and professor for photon science at SLAC and the study’s principal investigator. “These simulation tools could be applied to model other exotic material properties in extreme conditions.”
Reference: “Synthesis of Gold Hydride at High Pressure and High Temperature” by Mungo Frost, Kilian Abraham, Alexander F. Goncharov, R. Stewart McWilliams, Rachel J. Husband, Michal Andrzejewski, Karen Appel, Carsten Baehtz, Armin Bergermann, Danielle Brown, Elena Bykova, Anna Celeste, Eric Edmund, Nicholas J. Hartley, Konstantin Glazyrin, Heinz Graafsma, Nicolas Jaisle, Zuzana Konôpková, Torsten Laurus, Yu Lin, Bernhard Massani, Maximilian Schörner, Maximilian Schulze, Cornelius Strohm, Minxue Tang, Zena Younes, Gerd Steinle-Neumann, Ronald Redmer and Siegfried H. Glenzer, 4 August 2025, Angewandte Chemie International Edition.
DOI: 10.1002/anie.202505811
Parts of this work were supported by the DOE Office of Science.
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