Compute the atomic packing factor for the diamond cubic crystal structure (Figure 12.16)....

Compute the atomic packing factor for the diamond cubic crystal structure (Figure 12.16). Assume that bonding atoms touch one another, that the angle between adjacent bonds is 109.5°, and that each atom internal to the unit cell is positioned a/4 of the distance away from the two nearest cell faces (a is the unit cell edge length).

Figure 12.16 A unit cell for the diamond cubic crystal structure.