Question

Position of tetrahedral voids in fcc structure is:

• A. Edge centres of unit cell
• B. Two tetrahedral void on each body diagonal
• C. Face centres of unit cell
• D. Both (a) and (c)

Answer 1

The correct option is B Two tetrahedral void on each body diagonal

Two tetrahedral voids are present on each body diagonal of a fcc unit cell at a distance of $\frac{\sqrt{3}a}{4}$ from each corner. Totally, fcc unit cell will have 8 tetrahedral voids.