Scientists discover that gold is a 'reactive metal' by accidentally creating a new material in the lab
ByAdrian Villellas
Earth.com staff writer
https://www.earth.com/news/discovery-that-gold-is-reactive-metal-by-creating-gold-hydride-in-lab-experiment/
In a high-pressure lab experiment, scientists accidentally created a new compound called gold hydride. This particular hydride formed when thin gold foil met dense hydrogen at pressures hundreds of thousands of times Earth’s atmosphere and blazing temperatures.
... .. The work was led by Mungo Frost, a staff scientist at Stanford Linear Accelerator Center (SLAC) whose research probes materials under extreme pressures and temperatures.
Gold is usually chosen for experiments like this because it barely reacts, serving as a passive X ray absorber that heats surrounding material.
Gold was expected to remain inert during the experiment, since it is normally chemically unreactive and is routinely used as an X-ray absorber for that reason.
That accidental reaction produced the first confirmed solid compound made solely of gold and hydrogen atoms in any laboratory experiment. .... ...
... .. The team cranked the pressure until it rivaled Earth’s lower mantle, then blasted the sample with trains of X-ray pulses. ... .. Under pressure and heat, hydrogen became superionic, a state where atoms move like a liquid inside a solid, making the gold hydride conductive. ... In those environments, hydrogen is compressed so tightly that it behaves more like a dense, electrically conducting fluid than a simple gas. .... ...
Redefining “unreactive metals”
In everyday chemistry, gold is grouped with the noble metals that rarely form compounds, which is why jewelry stays bright for decades.
In these experiments, gold formed a hydride that held more hydrogen as pressure climbed, yet separated into plain gold again when conditions eased. .... ...
High pressure work has shown unreactive elements like xenon can form compounds, so gold hydride underscores how chemistry changes when matter is squeezed.
... Gold hydride’s appearance under stress shows that even familiar elements in lab samples can behave unexpectedly when scientists push conditions beyond normal experience. ... ...
The study is published in the National Library of Medicine.