Question

Are FCC and CCP the Same?

Answer 1

FCC stands for Cubic Structure Entered for CCP stands for Cubic Closed Packing.

1. The packing of atoms in an octahedral void is ABCABC, hence known as CCP, while the unit cell is FCC.
2. The unit cell is composed of four layers of atoms arranged in a cubic close-packed (CCP) arrangement.
3. The top and bottom layers (a) have six atoms at the hexagon corners and one atom at the center of each hexagon.
4. The atoms in the second layer (b) fit into the depression in the first layer.
5. The unit cell is composed of four layers of atoms arranged in a cubic close-packed (CCP) arrangement.
6. Each of the top and bottom layers have six atoms at the hexagon corners and one atom at the center of each hexagon.
7. The packing quality is the ratio of the atoms directly occupied by the crystal (or unit cell).
8. Because spheres (atoms are usually spherical) cannot be filled without empty space between them, it must often be less than 100 percent.
9. Face-centered cubic (FCC) and cubic close-packed same lattice (CCP) are two other names. We can think of this cell as being created by injecting another atom into each face of the simple cubic lattice - hence the term 'face-oriented cubic'.

Diagram:

Hence, FCC and CCP are not Same.