Are there tables for successive ionization energies for metals (like for gases)? All I can find are work functions to remove one electron from the surface of a metal into vacuum (and to keep it there). However, I guess it gets harder to remove electrons the more electrons already have been removed, right?

Maybe there's a way to relate that energy to the average degree of ionization of the material. Is it possible at all?

Finally, is it harder to ionize a metal gas or a metal solid? Although most work functions are a little bit smaller than the (1st) ionization-energies of the same material in gaseous state but I still think ionization of solids is harder. Am I correct?

  • $\begingroup$ Someone knowledgable should verify this, but i think that work functions are not related to ionization energies in a simple manner (except thaat work functions are always greater than ionization energies), because work function includes the average energy lost by the electron in collisions with other electrons and nuclei. If this is true, then work function would heavily depend on the crystal structure of the metal etc. $\endgroup$ Commented Aug 3, 2016 at 14:07
  • $\begingroup$ Also, if there is no such table you can find, you can always open Excel and copy the IE values from the Wikipedia pages of each metal you want. $\endgroup$ Commented Aug 3, 2016 at 14:09

2 Answers 2


In an infinite metal solid, there are an infinite number of electrons, so each one removed will be at the exactly identical work function with no change in energy.

Intuitively, this may seem a bit strange because .. well, it should be harder to remove an electron once positive charges start to accumulate.

If I have even a micron-sized piece of metal, that's ~$10^{13}$ atoms. So you really have to do a lot of ionization before you're even going to get 0.1% of the metal ions.


Here is the link to the exact page you want: Ionization energy of elements (Data Page)

For a good measure, here is the one for electron affinities too: Electron affinity (Data Page)

Wikipedia defines ionization energy as:

The ionization energy is qualitatively defined as the amount of energy required to remove the most loosely bound electron, the valence electron, of an isolated gaseous atom to form a cation.

This means we cannot really talk about the ionization energy for solid metals. The closest interpretation we can get for solid metals is the work function, but i suspect they depend on the metal's crystal structure too, as i have written below.

I would say that metal solids are harder to ionize because at low temperatures, the average energy of metal atoms is low and so thermal collisions generally may not have enough energy to knock an electron of a metal atom. A more important reason is that electrons are locked away in metallic bonds with other atoms (for solid metals), so you have to provide sufficient energy to the electron to not only break the metallic bonds, but also release the electron from the atomic nucleus. (Please correct me if i'm wrong.)

Also, check out this ionization energy page on Wikipedia for more information.

  • $\begingroup$ thanks for your reply but actually that tables give molar ionization energies for GASES, not for solids.... $\endgroup$
    – OD IUM
    Commented Aug 3, 2016 at 15:03
  • $\begingroup$ @ODIUM Okay, i misread your question! The first line made it seem that you wanted ionization energies for gases... well i don't know if there are ionization energy tables for solids... $\endgroup$ Commented Aug 4, 2016 at 4:55
  • $\begingroup$ @ODIUM Also please note that the Wikipedia page for IE says that IE is defined for isolated gaseous atoms (and ions). So the thing you are looking for is most likely not called ionization energy. Work function is the closest you can get (AFAIK), and that you can easily find. $\endgroup$ Commented Aug 4, 2016 at 4:57

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