In a cubic close packed structure, fractional contributions of an atom at the corner and at the face in the unit cell are, respectively

Question

In a cubic close packed structure, fractional contributions of an atom at the corner and at the face in the unit cell are, respectively (A) 1/8 and 1/2 (B) 1/2 and 1/4 (C) 1/4 and 1/2 (D) 1/4 and 1/8

Tardigrade Admin · Accepted Answer

The cubic lattice possesses 8 atoms on the corner. ∴ Fractional contribution by of atoms at the corner = (1/8). Each atom located at the face centered of ccp structure is shared between two adjacent unit cell and only (1/2) of each atom belongs to a unit cell. Thus, fractional contribution of each atom at face = (1/2)

Q. In a cubic close packed structure, fractional contributions of an atom at the corner and at the face in the unit cell are, respectively

$1/8$ and $1/2$

$1/2$ and $1/4$

$1/4$ and $1/2$

$1/4$ and $1/8$