Match the columns (assume the unit cell edge length equal to ) — Solid State Chemistry Question

💡 Solution & Explanation

(P) In fluorite, Ca$^{2+}$ are FCC (distance $a/\sqrt{2}$), and F$^-$ in TV (distance $a/2$). Two times these distances are $\sqrt{2}a$ (D) and $a$ (A). (Q) In NaCl, next nearest cations are at distance $a$ (A). (R) In CsCl, next nearest anions are at distance $\sqrt{2}a$ (D). (S) Distance of TV from corner is $\frac{\sqrt{3}a}{4}$; four times this is $\sqrt{3}a$ (C). (T) In anti-fluorite, O$^{2-}$ are FCC (next nearest distance $a$ $\rightarrow$ A), and Na$^+$ in TV (next nearest distance $a/\sqrt{2}$ $\rightarrow$ B). Therefore, correct pairs are A $\rightarrow$ P, Q, T; B $\rightarrow$ T; C $\rightarrow$ S; D $\rightarrow$ P, R.