Circa 2021 face_with_colon_three
Metallic non-metals
In theory, most materials are capable of becoming metallic if put under enough pressure. Atoms or molecules can be squeezed together so tightly that they begin to share their outer electrons, which can then travel and conduct electricity as they do in a chunk of copper or iron. Geophysicists think that the centres of massive planets such as Neptune or Uranus host water in such a metallic state, and that high-pressure metallic hydrogen can even become a superconductor, able to conduct electricity without any resistance.