Question

A crystalline solid $XY_3$ has $ccp$ arrangement for its element $Y. X$ occupies

• A. 33% of tetrahedral voids
• B. 33% of octahedral voids
• C. 66% of tetrahedral voids
• D. 66% of octahedral voids

Answer 1

Answer: (B)

33% of octahedral voids

Answer 2

In ccp arrangement, a unit cell has total 4 particles. To keep formula $X Y_{3}$, number of $X$ particles $=4 / 3=1.33$. Since, in ccp arrangement, octahedral sites $=4$ Therefore, percentage of $X$ particles occupying octahedral sites $=\frac{1.33}{4} \times 100=33 \%$