Question

In the basic $CsCL$ crystal structure, $C{s}^{+}$ and $C{l}^{-}$ ions are arranged in a bcc configuration as shown in the figure. The net electrostatic force exerted by the eight $C{s}^{+}$ ions on the $C{l}^{-}$ ions is

• A. $\frac{1}{4\pi {\epsilon }_0}\frac{4e^2}{3a^2}$
• B. $\frac{1}{4\pi {\epsilon }_0}\frac{16e^2}{3a^2}$
• C. $\frac{1}{4\pi {\epsilon }_0}\frac{32e^2}{3a^2}$
• D. zero

Answer 1

Answer: (D)

The given crystal structure is a body centered cubic structure.
The electrostatic force.
$F=\frac{1}{4\pi {\epsilon }_0}\frac{q_1{q}_2}{r^2}$
due to one $C{s}^{+}$ion is balanced by diagonally opposite $C{s}^{+}$ion. Hence, net electrostatic force on $C{l}^{-}$ion due to eight $C{s}^{+}$ions is zero.