Packings most-open arrangement

Most Open Packing—When spheres are piled so that each layer lies immediately above the other on a rectangular-base arrangement, we have the most open type of packing possible. Under these conditions the characteristics of the packing (called cubical) are as follows ... 

Contacts—The number of contacts experienced by a sphere in systematic packings is of considerable importance in the theory of capillary action of the soil. If we consider the arrangement in closest packing, it is evident that every sphere touches twelve other spheres. In the most open packing, contact is established with only six adjoining spheres. 

Figure 76. Geometric Arrangement of Spheres in Most-open and Closest Packings.

There are various theories on the structure of these species and their size. Some authors have assumed the presence of monomers and oligomers up to pentamers, with the open structure of ice I, while others deny the presence of monomers. Other authors assume the presence of the structure of ice I with loosely arranged six-membered rings and of structures similar to that of ice III with tightly packed rings. Most often, it is assumed that the structure... 

In addition to the close packed structures, other more open structures exist. The most important of these are the body centred cubic and the diamond, or zinc blende, structures. In the former structure, eight spheres are arranged at the corners of a cube and a ninth sphere at the centre of... 

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