The concept of magic numbers in the field of chemistry refers to a specific property (such as stability) for only certain representatives among a distribution of structures.
It was first recognized by inspecting the intensity of mass-spectrometric signals of rare gas cluster ions.
However, there are peaks at specific cluster sizes, deviating from a pure statistical distribution.
Therefore, it was concluded that clusters of these specific numbers of atoms dominate due to their exceptional stability.
The concept was also successfully applied to explain the mono-dispersed occurrence of thiolate-protected gold clusters; here the outstanding stability of specific cluster sizes is connected with their respective electronic configuration.