Hard-sphere packing fraction of diamond cubic
= Hard-sphere packing fraction of diamond cubic
{title2=$f=\pi\sqrt3/16$}
Nearest neighbors are separated by $a\sqrt3/4$, so touching spheres have radius $a\sqrt3/8$. Eight atoms in a conventional cell occupy fraction $\pi\sqrt3/16\simeq0.3401$. The underlying FCC <Bravais lattice> does not make this two-atom network close packed.