The smallest Cs-to-Cs inter-nuclear distance in the crystal is — Solid State Chemistry Question

💡 Solution & Explanation

CsCl has $Z=1$, meaning the unit cell volume equals the volume of 1 ion pair. $a^3 = 8 \times 10^{-23} \text{ cm}^3 = 80 \times 10^{-24} \text{ cm}^3$. Given $(4.3)^3 = 80$, $a = 4.3$ Å. The smallest Cs-to-Cs distance is $a$. Therefore, correct answer is B.