Question

$CsCl$ crystallises in body centred cubic lattice. If 'a' is its edge length, then which of the following expressions is correct?

• A. $r_{Cs^+} + r_{Cl^-} = 3a$
• B. $r_{Cs^+} + r_{Cl^-} = \frac{3a}{2}$
• C. $r_{Cs^+} + r_{Cl^-} = \frac{\sqrt 3}{2} a$
• D. $r_{Cs^+} + r_{Cl^-} = \sqrt 3 a$

Answer 1

Answer: (C)

$r_{Cs^+} + r_{Cl^-} = \frac{\sqrt 3}{2} a$

Answer 2

$2 r _{ Cl ^{-}}+2 r _{ Cs ^{+}}=\sqrt{3} a$
$r _{ Cl ^{-}}+ r _{ Cs ^{+}}=\frac{\sqrt{3} a }{2}$