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

Options

A. `r_(Cs^(+)) + r_(Cl^-) = sqrt(3)a`
B. `r_(Cs^+) + r_(Cl^-) = 3a`
C. `r_(Cs^+) + r_(Cl^-) = (3a)/(2)`
D. `r_(Cs^+) + r_(Cl^-) = (sqrt3)/2 a`

Answer

D

Explanation

Body diagonal = `sqrt(3)a`
or `2r_(Cs^+) + 2r_(Cl^-) = sqrt(3)a`
`:. r_(Cs^+) + r_(Cl^-) = (sqrt(3)a)/2`.