Scientists Were Wrong about Rust's Atomic Structure: New Findings

Scientists have taken a closer look at an elaborate type of rust, magnetite (Fe3O4) in order to learn a bit more about its properties. Since this material is playing and increasingly important role as a catalyst in electronic devices and medical applications, it's crucial to see its full potential.

In this case, the researchers examined the atomic structure of magnetite. Although scientists believed that its structure was well-established, the researchers found that it had been wrong all along. The properties of magnetite are governed by missing iron atoms in the sub-surface layer.

"It turns out that the surface of Fe3O4 is not Fe3O4 at all, but rather Fe11O16," said Ulrike Diebold, one of the researchers, in a news release.

This particular unusual surface gives magnetite unusual properties. Single atoms placed on the surface, such as gold or palladium, stay perfectly in place rather than balling up and forming a nanoparticle. This property makes the surface an extremely efficient catalyst for chemical reactions. Now, scientists have found out that it's missing iron atoms that do the trick.

Instead of a fixed structure of metal atoms with built-in oxygen atoms, think of iron-oxides as a well-defined oxygen structure with little metal atoms hiding inside. Directly below the outermost atomic layer, the crystal structure is rearranged and some iron atoms are absent. This causes other metal atoms to attach above the places of missing iron atoms. Since the vacant areas are regularly spaced, there is always some well-defined distance between gold or palladium atoms.

"Our results show that there is no need to despair," said Gareth Parkinson, one of the researchers. "Metal oxides can be modeled quite accurately after all, but maybe not in the way one might expect at first glance."

The findings could help researchers rethink crystal structures and boost iron-oxide research.

The findings are published in the journal Science.

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