Definition of a cluster [closed]








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Wikipedia defines a cluster as an ensemble of bound atoms or molecules that is intermediate in size between a molecule and a bulk solid. What is meant by a bulk solid? I can't find a definition anywhere? Further, is this a good enough definition?




The properties of a cluster depend on the exact number of constituents, and the geometry of the arrangement.


The properties of a bulk solid otoh are just indifferent to the exact size of the specimen (e.g. crystallite).


(In between you have nanocrystalline substances, where properties change with size, but only gradually.)


I would say that clusters are much like molecular compounds in that they have a distinct structure and absolute composition, however they are held together not by covalent bonds but by polar or dispersive forces (also metallic), and they usually consist of a number of identical particles.


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