Is a single molecule of sodium chloride (say) or a cluster of molecules of NaCl unstable, although macroscopically NaCl is in fact, stable? How can I reason this based on Earnshaw's theorem?
There is a related question in Is NaCl vapour plasma?. According to my answer to that question this paper states that sodium chloride vapour contains NaCl molecules, dimers and indeed polymers, so these are all stable. However when I've just tried the link I got an error from the AIP server. Some Googling found a similar and possibly the same paper here.