Lattice:HCP

HCP (Hexagonal close-packed) is a hexagonal lattice. It is notable (along with FACC) because it achieves the densest possible packing of spheres. It thus arises naturally in many atomic crystals, as well as in colloidal crystals and nanoparticles superlattices.

Canonical HCP

In the canonical HCP, the ratio between the a and c distances is:

${\frac {c}{c}}={\sqrt {\frac {8}{3}}}\approx 1.633$

Examples

Elemental

4. Beryllium (Be) (a = 2.290 Å, c = 3.588, c/a = 1.567)

Cadmium (c/a = 1.886)

Atomic

• TBD

Nano

• TBD

See Also

• Wikipedia: Close-packing of equal spheres