An ionic crystalline solid, , has a cubic unit cell. Which of the following arrangement of the ions — Solid State Chemistry Question

💡 Solution & Explanation

M ions at corners give $8 \times (1/8) = 1$ atom. X ions at face centres give $6 \times (1/2) = 3$ atoms. This matches the 1:3 ratio required for $\text{MX}_3$. Therefore, correct answer is A.