Cubic close packing is highly efficient and 74% space in the crystal is filled.
Cubic closed packing (CCP)
- The unit cell consists of four layers of atoms in a cubic close-packed arrangement of atoms.
- The layers at the top and bottom contain six atoms at the hexagon corners and one atom at the middle of each hexagon.
- The packing quality is the proportion of the atoms directly occupied by the crystal.
- It must often be less than 100 percent, since spheres can not be filled without any empty space between them.