Review Page: Sites in metallic lattices
The lattice for many ionic solids can be described as a either face-centred or cubic lattice of one ion with the second ion occupying spaces between the spheres known as sites. Below are characteristics of the various types of sites developed in the Metallic Solids module.
There are two types of spaces in close-packed lattices.
Octahedral sites are surrounded by six spheres and are at the center of each edge and the centre of the unit cell for the face-centred cubic lattice.
Tetrahedral sites are surrounded by four spheres. In the face-centred cubic unit cell, there is a tetrahedral site are under each corner sphere on the body diagonal. The spheres surrounding one of these are highlighted in the image at the right. These sites are each completely inside the unit cell.
The spaces in simple cubic lattice are referred as a cubic sites and are located at the centre of the unit cell. Cubic sites are surrounded by eight spheres.
Octahedral sites are surrounded by six spheres and are at the center of each edge and the centre of the unit cell for the face-centred cubic lattice.
Roll your mouse over the image at the right to see the octahedral site at the centre of the face-centred cubic unit cell.
Tetrahedral sites are surrounded by four spheres. In the face-centred cubic unit cell, there is a tetrahedral site are under each corner sphere on the body diagonal. The spheres surrounding one of these are highlighted in the image at the right. These sites are each completely inside the unit cell.
The spaces in simple cubic lattice are referred as a cubic sites and are located at the centre of the unit cell. Cubic sites are surrounded by eight spheres.