I understand that sodium chloride when solid, is a lattice, so NaCl there is an empirical formula,(so, expresses that the ratio of Na to Cl is 1-1), and not a molecular formula expressing exact numbers of atoms.

I was looking at this question which covers what sodium chloride is like in gas state. What is Sodium Chloride like in gas state?

And it mentions that in gas form, you get an NaCl monomer, and $\ce{Na2Cl2}$ dimer. That's mentioned in the abstract https://pubs.acs.org/doi/10.1021/jp073328o. And those are molecules, not like with the sodium chloride lattice.

But what about for sodium chloride as liquid. What form does sodium chloride take there?

  • $\begingroup$ @OscarLanzi so would you say it's not a monomer en.wikipedia.org/wiki/Monomer or dimer? (or would you say that a monomer or a dimer, isn't necessarily a molecule)? $\endgroup$
    – barlop
    Jan 6, 2022 at 15:52
  • $\begingroup$ You can certainly have monomeric ion pairs. $\endgroup$ Jan 6, 2022 at 15:59
  • 1
    $\begingroup$ A good starting point to check is moltensalt.org/whatIsMoltenSalt.html. It is essentially high-temperature ionic liquid, whereas the topical room-temperature ionic liquid (RTIL) is essentially ambient-temperature molten salt. I think a key property to understand the ion associations in molten salt is radial distribution function. There are lots of molecular dynamics simulations, even from decades ago. $\endgroup$
    – Josiah_H
    Jan 6, 2022 at 18:02
  • $\begingroup$ @OscarLanzi Well, I would sure call them molecules. Ion pairs are in cases like here: chemistry.stackexchange.com/questions/136299/… $\endgroup$
    – Mithoron
    Jan 6, 2022 at 18:26
  • 2
    $\begingroup$ More to the point, liquid NaCl isn't much different then solid, but average coordination number is lower. $\endgroup$
    – Mithoron
    Jan 6, 2022 at 18:28


Your Answer

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

Browse other questions tagged or ask your own question.