It’s been called one of the Holy Grails of chemistry—finding out how certain catalysts actually work. And it is not just something of academic interest. Understanding catalytic reactions is of great economic importance for many industries where even a small improvement in catalytic efficiency can save energy and raw materials.

In the oil refining process, for example, hydrogen is removed and carbon added to extend a chain of carbon atoms. “Catalysts have been developed to facilitate reactions of hydrocarbons, but it has been more like alchemy because, until now, we didn’t know how this was working,” says Karsten Meyer, a UCSD assistant professor of chemistry and biochemistry.

As molecules react with each other to form new molecules, they rapidly transition through a highly unstable intermediate compound. Catalysts work by stabilizing this intermediate compound, and this reduces the amount of energy required to make a reaction occur. Understanding how a catalyst molecule interacts with a reactant molecule can inform the design of more effective catalysts. But molecules can be camera shy and capturing a molecule in action is particularly tricky.

To solve the problem, Meyer and his colleagues, including Arnold Rheingold, professor of chemistry and biochemistry, designed a model catalyst and used X-ray crystallography. This technique, in which X-rays are passed through crystals of a molecule, accurately revealing the locations of the atoms, gave the group precise information about the orientation of the atoms and the way in which the model catalyst activated a hydrocarbon reactant molecule.

The model catalyst consists of an atom of uranium in the center surrounded by three large cyclic groups of atoms. The researchers selected uranium because, as the heaviest naturally occurring element, it is large, electron rich, and able to effect many different chemical reactions. X-ray crystallography revealed that a group of atoms in the model compound provides a pocket around the top of the uranium atom in which the hydrocarbon molecule is altered by contact with the uranium atom.

These findings provide a snapshot of how modern catalysts work. “Using X-ray crystallography, we have been able to show exactly how the atoms in the reactant molecules and catalyst interact, and this information could make it possible to design super-effective catalysts,” says Meyer.

Which may just prove to be a boon for the oil and gas industries and maybe even for us, the consumers.