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