Serendipitously and for the first time, an international research team led by scientists at the U.S. Department of Energy’s SLAC National Accelerator Laboratory formed solid binary gold hydride, a compound made exclusively of gold and hydrogen atoms.

The researchers were studying how long it takes hydrocarbons, compounds made of carbon and hydrogen, to form diamonds under extremely high pressure and heat.

In their experiments at the European XFEL (X-ray Free-Electron Laser) in Germany, the team studied the effect of those extreme conditions in hydrocarbon samples with an embedded gold foil, which was meant to absorb the X-rays and heat the weakly absorbing hydrocarbons. To their surprise, they not only saw the formation of diamonds, but also discovered the formation of gold hydride.