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Isoelecronic atoms have same number of electrons but different nuclear charge. It is said that many of the chemical properties of these elements are equal or at least similar.

Can I form solids with isoelectronic atoms and how do their band structures differ with respect to the standard versions of the solids?

To make a specific example, take a bunch of Nickel atoms, ionize each of them 2 times, then you have a bunch of Iron-like Nickel atoms. Get them together and let them form a iron solid metal compound. Does this formation happen? What is the band gap with respect to the normal Iron band gap?

I expect that making solids out of only isoelectronic atoms might not be possible, since the electrostatic repulsion prevents chemical bonds from forming. However, let us say that I want to make a solid compound with some iron atoms and some iron-like nickel atoms. How does the band gap changes in general with the doping level?

Thanks!

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    $\begingroup$ Heck, making doubly charged diatomics is hard enough (cf. this). Electrostatic repulsion is strong, and putting together lots of charged matter right next to each other tends to result in a Coulomb explosion. Similarly, you can't dope iron with nickel ions, as you have no guarantee that the nickel will remain ionized. (Instead, you'll just get a delocalized hole moving about the metal.) $\endgroup$ – Emilio Pisanty Oct 25 '15 at 20:22
  • $\begingroup$ It would be awesome if you could turn up the nuclear charge as felt by the electrons but not as felt by other nuclei in the crystal, but sadly this is impossible in experiments. You could try it in numerics, of course! It's unlikely that it's been done before, though, because it is so far from a physical situation. $\endgroup$ – Emilio Pisanty Oct 25 '15 at 20:23
  • $\begingroup$ Thanks. So, unlike what is often said, chemical properties of isoelectronic atoms are very different. They just don't bind. Now I would ask: How does the band gap changes if I remove some electrons from the solid or insulator (by photoionization for ex)? $\endgroup$ – Wizzerad Oct 25 '15 at 21:33
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    $\begingroup$ The atomic properties - energy levels, polarizability, and so on - of isoelectronic atoms are very similar. If someone told you that the chemical properties of an atom remain much the same if you magically turn it into an ion, and you believed them at face value - well, you've only yourself to blame. $\endgroup$ – Emilio Pisanty Oct 25 '15 at 21:56
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    $\begingroup$ If that is your new question, you should edit it to reflect it. You should make clear what degree of ionization you're contemplating. Is it a housekey set to 1V w.r.t. ground? or are you removing one electron from every other atom? The answer will depend on that. $\endgroup$ – Emilio Pisanty Oct 25 '15 at 21:58

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