Question

The total number of tetrahedral voids in face centered unit cell is ______.

• A. 6
• B. 8
• C. 10
• D. 12

Answer 1

The correct option is B 8

In face centered cubic unit cell (FCC), tetrahedral voids are present on body diagonals. There are two tetrahedral voids on each body diagonal at ${\left(\frac{1}{4}\right)}^{th}$ of the distance from each corner.

So, total number of tetrahedral voids = (no. of tetrahedral voids per body diagonal) x (no. of body diagonals) = $2\times 4=8$

Hence, Option "B" is the correct answer.