Atoms of the element 'A' form HCP and atoms of element 'C' occupy only two-third of octahedral voids — Solid State Chemistry Question

💡 Solution & Explanation

Let the number of 'A' atoms in the HCP lattice be $N$. The number of octahedral voids generated is also $N$. Since 'C' atoms occupy $2/3$ of these voids, the number of 'C' atoms is $\frac{2}{3}N$. The ratio of C to A is $\frac{2}{3}N : N$, which simplifies to $2:3$. Hence, the formula is $C_2A_3$. Therefore, correct answer is C.