Common sphere packings taken on by atomic systems are listed below with their corresponding packing fraction.
* Hexagonal close-packed (HCP): 0.74
* Face-centered cubic (FCC): 0.74 (also called cubic close-packed, CCP)
* Body-centered cubic (BCC): 0.68
* Simple cubic: 0.52
* Diamond cubic: 0.34
The majority of metals take on either the HCP, FCC, or BCC structure.