Why gold resists oxidation hinges on atomic zigzags

gold resists – Gold’s long-lasting shine isn’t just luck in chemistry. A new Physical Review Letters paper by Tulane University researchers Santu Biswas and Matthew Montemore links gold’s resistance to oxidation to how its atoms rearrange into a zigzag “herringbone” pattern

For most metals, the story is simple: air comes in, oxygen sticks, and the surface slowly changes. Gold has never followed that script. It keeps its shine far longer than most, and now two researchers have put a precise mechanism behind the magic.

In a paper published today in Physical Review Letters. Santu Biswas and Matthew Montemore of Tulane University describe why gold is harder to oxidize than similar metals. Their explanation centers on the intricate “herringbone” pattern of gold’s atoms—an arrangement visible under a scanning tunneling microscope when the surface is examined closely.

“Everyone knows that gold is difficult to oxidize,” Biswas says. “The thing is, why? What is the proper reason for that?”

Oxidation is the process in which oxygen—or another element such as sulfur—reacts with a metal and attaches to its surface. For iron. the buildup of bonded oxygen is commonly called “rust. ” while oxidation of other metals is often referred to as “tarnish.” How easily oxygen attaches depends on how a metal’s atomic structure holds onto electrons. Gold is already known to “treasure its electrons and spurn donations from outside. ” preserving its shine and supporting its use in jewelry and various industrial applications.

But Biswas and Montemore argue that gold’s tightly held electrons don’t fully explain why oxygen struggles to do its work.

Their hunch turned on what happens the moment a fresh surface is exposed. If you cleave a chunk of gold, the newly exposed face doesn’t just sit there. It reshapes itself in seconds. The atoms rearrange into a zigzagging “herringbone” pattern through a phenomenon called “surface reconstruction.”

To test what that rearrangement changes, the team calculated the energy required to oxidize gold before and after this reshuffling. They found that oxygen molecules from the air—each made of two oxygen atoms bonded together—more easily break apart and adhere to gold atoms on the surface before the pattern is reestablished. In that brief instant when a new surface is exposed, the reaction requires much less energy.

Once the herringbone pattern snaps back into place, the rules change. The reconstruction pulls more gold atoms out from the metal’s bulk, jamming them into the surface. It also turns a simple, square-shaped atomic lattice into a denser hexagonal shape. That structural shift produces the bumps and ridges seen in the pattern—and it steers the surface closer to thermodynamic equilibrium.

The advantage for gold is that it becomes harder for oxygen to wedge into the reorganized surface.

The work ends with a practical possibility: the same mechanism that protects gold can also be interrupted. “You can prevent reconstruction by putting some absorbent on top of the surface,” Biswas says. “And then the gold can easily oxidize.”

If that approach holds up. the findings could point to a new direction for chemists—using gold surfaces not just as corrosion-resistant materials. but as tools to capture oxygen from gases. Keeping gas streams pure is often a key challenge. and the paper suggests that controlling reconstruction could become a lever for doing it.

gold oxidation herringbone pattern surface reconstruction Physical Review Letters Tulane University atomic structure electron behavior corrosion chemistry oxygen capture