Packing of Spheres

You can read up on this topic in Housecroft and Constable 3rd Edition pages 301 to 308

You need to understand these important structures, and be able to draw simple diagrams to represent them. Some of the main features of these structures are summarised below, and there are links to pages where you can examine some more detailed pictures.

Note that the packing efficiency of a structure increases as the coordination number of an atom in the structure increases.

Some of these structures are important in understanding the structures of ionic solids.

 
simple cubic
body centred cubic

face centred cubic

hexagonal close packed
 
coordination number
6
8
12
12
packing efficiency
52%
68%
74%
74%
example
Po
Fe
Cu
Mg
more information

CHEM111 structures