The crystalline structure of a solid is CCP for 'X' atoms. If 'Y' atoms occupy all the octahedral vo — Solid State Chemistry Question

💡 Solution & Explanation

Total length along body diagonal = $\sqrt{3}a \approx 4.899 R_X$. Length covered by atoms = $2R_X \text{ (corners)} + 4(0.225 R_X) \text{ (tetrahedral Z)} + 2(0.414 R_X) \text{ (octahedral Y)} = 3.728 R_X$. Fraction not covered = $\frac{4.899 - 3.728}{4.899} = \frac{1.171}{4.899} \approx 0.239 \approx 0.24$. Therefore, correct answer is B.