Q. $CsBr$ crystal has bcc structure. It has an edge length of 4.3 $\mathring{\mathrm{A}}.$ The shortest interionic distance between $Cs^{+}$ and $Br^{-}$ ions is
A) 1.86 $\mathring{\mathrm{A}}$
B) 2.86 $\mathring{\mathrm{A}}$
C) 3.72 $\mathring{\mathrm{A}}$
D) 4.72 $\mathring{\mathrm{A}}$
Explanation
(c)
Closest approach in bcc lattice
$= \frac{1}{2}$ of body diagonal $= \frac{1}{2} \times \sqrt{3}a$
$= \frac{\sqrt{3}}{2} \times \ 4.3 = 3.72\ \mathring{\mathrm{A}}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.