Gold has resisted tarnish for thousands of years, its shine enduring on ancient coins and artefacts. A study from Tulane University now shows this property stems not only from weak chemical interaction with oxygen but from a remarkable atomic rearrangement at the surface.
Researchers used computer simulations to examine how oxygen molecules interact with common gold facets. Atoms on the Au(110) and Au(100) surfaces naturally rearrange into quasihexagonal structures. These patterns create a high barrier to oxygen dissociation.
The reconstruction slows the process by many orders of magnitude compared with unreconstructed rectangular or square surfaces. Without it, gold would likely oxidise quickly under ambient conditions. The effect suppresses oxygen reactions by a factor of a billion to a trillion.
Matthew Montemore, associate professor in Chemical Engineering at Tulane University, said: People have generally thought gold does not tarnish simply because it does not interact strongly with oxygen. What we show is that for two of the most common gold surface types, the surface atoms actually rearrange themselves in a way that makes the gold much more resistant to oxidation.
This finding underscores the enduring power of classical empirical materials science. Rooted in centuries of Western observation and experiment, such work delivers precise insights into natural properties. It proceeds through private and academic institutions without reliance on expansive regulatory oversight.
The paper, titled Role of Reconstruction in the Inertness of Gold toward Oxygen, appeared in Physical Review Letters on 21 May 2026. Led by Montemore and Santu Biswas, the simulations relied on quantum mechanical modelling rather than direct laboratory samples of gold.
The results also carry practical weight. Creating square or rectangular gold surfaces, which lack this protective rearrangement, could improve catalytic activity for oxidation reactions. Montemore pointed to one route forward.
