Noble gases and uranium get cozy. (Chemistry).

Noble gases are notorious for their extreme disinterest in bonding with other elements. For this reason, scientists have had to work hard to force gases such as argon into stable compounds (SN: 8/26/00, p. 132).

Scientists have now created a compound containing argon and uranium--by accident no less. It's the first-ever compound containing both a noble gas and one of the periodic table's so-called actinide elements.

Researchers at the University of Virginia in Charlottesville and Ohio State University in Columbus were studying the reaction of uranium (U) with carbon monoxide (CO) when they made the serendipitous discovery. In their experiments, the scientists were initially creating CUO molecules in an atmosphere of neon, a noble gas.

But when the team tried the same experiment with argon gas instead of neon, spectroscopic analysis of the product suggested that the argon wasn't so inert. Further experiments and calculations convinced the researchers that the CUO molecule had actually bonded to argon and formed a new compound, says Ohio State chemist Bruce Bursten. Additional work indicated that other noble gases--krypton and xenon--also bond with uranium to create previously unknown compounds.

The uranium-noble gas bonding is "a neat chemical curiosity that needs to be explored further," says Bursten. He and his colleagues report their results in the March 22 Science. --J.G.