Question

In an FCC unit cell, if a cube is formed by joining the centers of all the tetrahedral voids to generate a new cube, then the new cube would contain voids as :

• A. $1$ full tetrahedral void and $1$ full octahedral void
• B. $1$ full tetrahedral void only
• C. $8$ full tetrahedral voids and $1$ full octahedral void
• D. $1$ full octahedral void only

Answer 1

The correct option is A $1$ full tetrahedral void and $1$ full octahedral void

No. of tetrahedral voids $=8\times \frac{1}{8}=1$
No. of octahedral voids $=1\times 1=1$ (at body center)