Difference between revisions of "Lattice:HCP"
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In the canonical HCP, the ratio between the ''a'' and ''c'' distances is: | In the canonical HCP, the ratio between the ''a'' and ''c'' distances is: | ||
:<math> | :<math> | ||
| − | \frac{c}{ | + | \frac{c}{a} = \sqrt{ \frac{8}{3} } \approx 1.633 |
</math> | </math> | ||
Revision as of 10:01, 14 October 2014
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:
Examples
Elemental
- 4. Beryllium (Be) (a = b = 2.290 Å, c = 3.588, c/a = 1.567)
- 27. Cobalt (Co) (a = b = 2.5071 Å, c = 4.0695, c/a = 1.623)
- 48. Cadmium (Cd) (a =b = 2.9794 Å, c = 5.6186 Å, c/a = 1.886)
Atomic
- TBD
Nano
- TBD
