Question

Select correct statement(s) for FCC arrangement:

• A. Number of octahedral voids surrounding one octahedral voids is 12.
• B. Number of tetrahedral voids surrounding one tetrahedral void is 6.
• C. Number of octahedral void surrounding one tetrahedral void is 4.
• D. Number of tetrahedral voids surrounding one octahedral void is 8.

Answer 1

Answer: (A), (B), (C), (D)

A, B, C, D

Answer 2

The FCC lattice has atoms at corners and face centers. The number of atoms per unit cell is $Z = 4$.

There are 4 octahedral voids (OV) per unit cell, located at the body center and edge centers.

There are 8 tetrahedral voids (TV) per unit cell, located at the positions like $(\pm 1/4, \pm 1/4, \pm 1/4)$ relative to the origin at a corner.

Statement A is correct: Number of octahedral voids surrounding one octahedral void is 12.

Statement B is correct: Number of tetrahedral voids surrounding one tetrahedral void is 6.

Statement C is correct: Number of octahedral void surrounding one tetrahedral void is 4.

Statement D is correct: Number of tetrahedral voids surrounding one octahedral void is 8.