Another characteristic of the unit cell is the number of WHOLE atoms that it contains.
The lattices with their unit cell outlines show that for a cubic unit cell
The next few questions will use this information to calculate the number of atoms in total within the boundaries of each of the three cubic unit cells.
The contribution of each atom depends on its position in the unit cell.
Spheres are cut into segments by the perpendicular planes forming the faces of a cubic unit cell just as an orange is cut into segments with a knife.
Spheres are cut into segments by the perpendicular planes forming the faces of a cubic unit cell just as an orange is cut into segments with a knife.
The lattices with their unit cell outlines show that for a cubic unit cell
- body-centred atoms are completely inside.
- corner atoms contribute 1/8
They are cut in half by three successive planes).
Viewed from a different perspective,each corner atom is shared by 8 unit cells. - face atoms contribute 1/2
They are cut in half by one plane. - Viewed from a different perspective, each face atom is shared by 2 until cells.
The next few questions will use this information to calculate the number of atoms in total within the boundaries of each of the three cubic unit cells.