Noble gases—radon, xenon, krypton, argon, neon, and helium—are snobs. Their atoms typically shun liaisons with other elements because they already have all the electrons they need, but none to share. Only when chemists engage in forced matchmaking do some of these gases react with other elements to form stable, neutral compounds.
Researchers at the University of Helsinki in Finland report in the Aug. 24 Nature that the formerly aloof argon has been coerced into the chemical equivalent of a shotgun wedding.
The scientists made the new compound, argon fluorohydride (HArF), by shining a strong ultraviolet light on frozen argon that contained a small amount of hydrogen fluoride. The light split some of the hydrogen fluoride molecules into hydrogen and fluorine atoms, which then combined with argon to form the new compound, says Markku Räsänen, an author of the report. The resulting mixture absorbed wavelengths of infrared light that theorists had pred