A Noble Gas Surprise: Helium Can Form Weird Compounds
Published:27 Apr.2018    Source:Scientific American
Helium, the most noble of the noble gases, long thought to be completely inert and thus too standoffish to bond with other atoms, recently surprised chemists by forming chemical compounds after all.
 
Last year scientists reported producing the compounds—crystals made of sodium and helium atoms—but could not understand how they formed. Now a new team of researchers has offered an explanation: Helium manages to combine with other atoms without making any chemical bonds—that is, without sharing or exchanging any electrons. The element does this by shielding positively charged atoms from each other, acting as a buffer between their repellent charges. “They have proposed an explanation, and I like it,” says Artem Oganov, a chemist at the Skolkovo Institute of Science and Technology in Russia and leader of the group that initially discovered the helium compounds. “This model is predictive and it explains all the observations we have so far.”