9
$\begingroup$

I was reading that hydrogen can become a metal in some cases, like in Jupiter, and the same for helium. Is this true for all non-metals?

$\endgroup$
4
  • 7
    $\begingroup$ Hydrogen is special because its the only member of its period and has a half-filled valence shell, so it can both lose or gain electrons. This is not the case with all non-metals. $\endgroup$ Commented Sep 14, 2018 at 15:32
  • 1
    $\begingroup$ I think that it's generally believed that if one compresses any material enough that it will eventually turn into a metal because moving the atoms closer together tends to broaden the electronic bands, leading to possible band-overlap metallization and turning localized electrons into itinerant electrons. Don't know if there's any general proof of that, though. $\endgroup$
    – user93237
    Commented Sep 14, 2018 at 16:54
  • 1
    $\begingroup$ Also, no, there's nothing special about hydrogen. The non-metallic elements oxygen, nitrogen, and xenon have all been metallized by the application of high pressures. $\endgroup$
    – user93237
    Commented Sep 14, 2018 at 17:00
  • 1
    $\begingroup$ Try approaching this from the other side : here's a page with a List Of Elements that are Non-Metals. You also need a clear definition of "metal" to answer the question, which is a problem as it's a somewhat loose term. $\endgroup$ Commented Sep 14, 2018 at 17:41

1 Answer 1

4
$\begingroup$

Assume you have a bunch of atoms consisting of some electrons in a bound state around a heavy core. If you increase the density($n$), you will eventually reach a point where the electrons Fermi energy($\sim n^{\frac{2}{3}}$) will be higher, then the binding energy of the outer electrons of your atoms, which will result in pressure ionization. You now have a system of positive ions, the kinetic energy of which depends on the temperature (their Fermi energy will be orders of magnitude lower then the electrons one because of their higher mass), and weakly interacting electrons, whose high kinetic energies will be independent of the temperature. If your temperature is sufficiently low, the positive ions will form a Coulomb crystal. You then have a solid containing electrons not bound in an atom, which is, what I would describe as metal. In my mind this could be realized independently of what element you are looking at.

So my answer is yes, any element should behave as a metal, if the density is high enough to produce degenerate electrons, but low enough, that the ions are non degenerate, and the temperature is low enough that the ions form a crystal.

$\endgroup$
1
  • $\begingroup$ It would be an interesting exercise in condensed-matter physics to quantitatively predict the conditions of this metallic phase for some classic non-metals, or to flip it around and predict non-metallic phases for some traditional metals. $\endgroup$
    – rob
    Commented Mar 31 at 18:21

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.