In a surprising breakthrough, researchers have created a new compound called gold hydride by exposing gold foil to dense hydrogen at crushing pressures and intense heat, challenging the long-held belief that gold is one of the least reactive metals. Gold typically sits in the “noble” category of elements, prized for its resistance to corrosion and chemical change. Under everyday conditions, it hardly forms compounds — a reason it’s widely used in jewelry and electronics. But in a high-pressure laboratory experiment designed to study how hydrocarbons turn to diamond, scientists observed hydrogen atoms entering gold’s atomic lattice and forming solid gold hydride. This new material exists only under extreme pressures and temperatures far beyond Earth’s surface norms, conditions akin to the deep interior of giant planets or stars.

The experiment — carried out with powerful X-ray lasers and a diamond anvil cell capable of generating pressures over 40 gigapascals — revealed hydrogen moving through gold’s structure in what researchers call a superionic state, where hydrogen atoms flow like a fluid inside the solid metal framework. This behaviour not only reframes how chemists understand gold’s reactivity but also offers a new platform to study dense hydrogen, a key ingredient in planetary science and fusion research.

Although gold hydride reverts to ordinary gold once conditions relax, the discovery highlights that extreme environments unlock unexpected chemistry, suggesting other “unreactive” elements might also form exotic compounds under similar forces.