Gold has long been considered one of the most unreactive metals on Earth, valued for its stability and resistance to chemical change. But scientists have now discovered that under extreme pressure and heat, gold can behave very differently. In a high-pressure laboratory experiment, researchers accidentally created a brand-new material called gold hydride, overturning gold’s reputation as an almost inert metal.
The discovery happened during an experiment designed to study how hydrocarbons transform into diamonds under crushing pressure and intense heat. Scientists placed tiny samples between the tips of a diamond anvil cell, a device capable of recreating conditions found deep inside planets. A thin foil of gold was included in the setup simply to absorb X-rays and heat the surrounding material, as gold is normally chemically passive.
Under pressures hundreds of thousands of times greater than Earth’s atmosphere and temperatures above 3,500 degrees Fahrenheit, something unexpected occurred. Hydrogen atoms, released from the compressed hydrocarbons, entered the gold’s crystal structure and bonded with it. This formed gold hydride, the first confirmed solid compound made only of gold and hydrogen ever produced in a laboratory.
The experiment was led by Mungo Frost, a scientist at the Stanford Linear Accelerator Center. Using powerful X-ray pulses from the European XFEL facility in Germany, the team tracked changes inside the sample. While carbon atoms formed the neat lattice of diamond as expected, subtle changes in X-ray scattering revealed that hydrogen atoms were moving into the gold lattice, altering its structure.
At these extreme conditions, hydrogen entered a rare state known as superionic, where it behaves like a liquid while remaining within a solid structure. In this form, hydrogen could move rapidly through the gold lattice, making the material electrically conductive. When the pressure and temperature were reduced, the hydrogen separated and the gold returned to its familiar, unreactive form.
This accidental breakthrough has major implications beyond chemistry. Dense hydrogen is believed to exist deep inside giant planets like Jupiter, where it plays a role in generating magnetic fields and transporting heat. Gold hydride now provides scientists with a controlled way to study how hydrogen behaves under such extreme conditions, offering valuable insights into planetary interiors.
The findings could also aid nuclear fusion research. Fusion depends on accurately understanding how hydrogen behaves at enormous pressures and temperatures. Even small uncertainties can affect predictions, and gold hydride offers a new benchmark for testing and improving fusion models.
More broadly, the discovery challenges the idea of “unreactive” elements. Previous high-pressure research has shown that even noble gases like xenon can form compounds under extreme conditions. Gold hydride adds to this growing evidence that chemistry changes dramatically when matter is pushed far beyond normal environments.
As experimental tools such as diamond anvil cells and high-energy X-ray lasers continue to improve, scientists expect to uncover more exotic materials that exist only under intense pressure and heat. The creation of gold hydride shows that even the most familiar elements can surprise us when taken to extremes, opening new windows into planetary science, fusion research and the fundamental behavior of matter.