# Is it possible create crystalline solvate of electrons?

Okay, I know that this reads ridiculous insane, but one can obtain solvated electrons by adding sodium metal to liquid ammonia solution.

The chemical reaction as written in my inorganic chemistry textbook is this:

$$\ce{Na + x NH3 -> Na+ + e(NH3)_x-}$$

A metallic sheen is observed, and it supposed to have an absorption band at about $1500\ \mathrm{nm}$ that expands into the range of visible light corresponding to the solvated electrons.

These electrons can be react with alkynes as very powerful reducing agents to to remove an H from a C joined by a triple bond, also liberating hydrogen gas as such. This occurs in the solution made by an alkali metal, not from pure extracted electrons

$$\ce{RC#CH + e- -> RC#C- + 1/2 H2}$$

So I was wondering if pure electrons can be solvated in ammonia, if anyone could think of any means by which these electrons could be extracted from the layer, still solvated by ammonia, and some reaction chemistry could be used to trap electrons in a carbon cage in the form of a solid? It is already known that potassium can be electrostatically trapped in valinomycin between the carbonyl groups of valinomycin.

While it may be different small molecules have been trapped in fullerenes. If electrons could be solidified via extracting them from the metallic layer in the proposed reaction, and interacting them with a "host molecule" in host-guest chemistry, do you think that these materials would be highly conductive. It seems to me that captured electrons would have a much different chemistry than simply metals like copper which shed electrons when a current runs through them. Perhaps if these electrons could be absorbed into carbon nanotubes, then the conductivity of nanotubes would increase significantly and these electron complexes may be significantly more powerful computationally than silicon chips.

Here is an experiment by the University of Nottingham scientists showing the solvation of electrons: https://www.youtube.com/watch?v=tYjQXjUUvwY

What do you think about this? Any ideas?

• Coulombic charge repulsion should make captured, solid electrons impossible. – BiggChemT Nov 9 '16 at 3:04
• Electrostatic repulsion is the main problem. For the same reason it would be impossible to obtain in bulk quantities some highly radioactive elements that undergo beta decay. – vapid Nov 9 '16 at 7:58
• It seems you're asking about solid electrides. These are very real and very interesting materials. – Nicolau Saker Neto Nov 9 '16 at 11:59
• Here's another very useful resource for electrides ch.imperial.ac.uk/rzepa/blog/?p=14272 from Prof Rzepa ... his blog is well worth studying. – user1945827 Apr 14 '17 at 7:47
• @NicolauSakerNeto I think that would make for an interesting answer. – Tyberius Oct 6 '17 at 16:54

## 1 Answer

At first I would like to advise you reading about electrides, which were mentioned in the comments. Secondly I won't write about electrides because the links given in the comments are much better at explaining them. So I am going to be a little bit abstract with this question.
The first problem which you will come through is Coulomb's law: $$\mathbf F=\frac{1}{4\pi \epsilon_{0}}\frac{Q_{1}Q_{2}}{|\mathbf r|^{2}}\frac{\mathbf r}{|\mathbf r|}$$ If you could somehow prepare even $0.01$ moles of electrons, they would be attracted to the ions which they were separated from very strongly even from kilometers away. The second problem is that electrons can't be simply trapped into any substance because of their wavelike nature and they would tend to "stay" in a localised or in a delocalised state in the molecoules. And here comes the two main things which are preventing such things to exist:
1. Charge distribution
If a conducting body is charged, the charge tends to build up on the edges, and in your situation the repulsive force between the electrons would be so huge, they would "kick" each other off on the edges of the pieces of the substance so it would loose it's electrons.An interesting phenomena such substance would have: Let's suppose the substance containing the electrons is a liquid. All the electrons would be located on the surface of the liquid because of the faraday effect.When the surface of the liquid is disturbed waves appear on it's surface. Let's suppose the electrons somehow can't be kicked off from the surface. Then there would always be electric current in the liquid because the elecrons would always try to get to the most sharp edge on the surface and the liquid would generate extremely complex magnetic fields because of the currents flowing on the surface of the liquid (I am so excited about the idea of such a liquid, I am so sad I have no idea how it would be possible to make it)
2. Quantum mechanics
The band gap determines if a substance is an insulator or a semiconductor or a conductor. And adding more electrons to something doesn't modify the band gaps. Like if I charge a plastic rod with electrons it won't become a conductor. But there is an alternative solution. If you dope the substance it can modify the band gap energy and it can be more conductive but you can't simply trap electrons in something (F-centers are a completely different story). Imagine irradiating carbon nanotubes with electrons. I wouldn't suspect it becoming more conducting .
Anyway the best source for pure electrons is an electron gun
If you want to deepen your knowledge about the nature of electrons and conductivity I advise you learning some solid-state physics, quantum mechanics and electromagnetism.(None of them is a light weekend program)