A common type of crystal structure has a cubic unit cell with atoms centered at all eight corners, plus a single atom in the center. The center and corner atoms touch each other along the cube diagonals. So therefore each atom only touches eight other atoms. This pattern holds two atoms per unit cell. The atomic packing factor for a Body Centered Cubic crystalline structure is 0.68.
Some of the materials that are composed of Body Centered Cubic unit cells at room temperature
, and Tungsten