Helium’s inertness defied by high-pressure compound
Crushing elements together with diamonds creates a rare mash-up
![helium sodium compound](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2017/02/021617_EC_helium_main.jpg?fit=860%2C460&ssl=1)
HELIUM COMPOUND Scientists created a chemical compound of helium and sodium by squeezing the elements to extremely high pressures. Helium atoms (green cubes) are arranged in a 3-D checkerboard structure, each surrounded by eight sodium atoms (purple). Electron pairs (red) sit in the spaces between helium atoms.
Courtesy of A.R. Oganov