An analysis is given of the properties of a cluster cut from a face-centered and a body-centered cubic lattice and also from a hexagonal crystalline lattice about a certain center. The clusters have a shell structure and contain tens and hundreds of molecules. The binding energies of molecules and the surface energy of the cluster are shown for different occupation numbers and for three types of structure of the cluster, and also for different temperatures. It is shown that the concept of surface tension is valid for clusters containing tens of molecules, but from the point of view of the binding energy of the surface molecules a cluster consisting of hundreds of molecules is not a macroscopic particle even at relatively high temperatures. An expression is obtained for the surface energy of a cluster.