Question

A solid has a BCC structure. If the distance of closest approach between the two atoms is $1.73\stackrel{\circ }{A}$. The edge length of the cell is-
($\sqrt{3}=1.73$)

• A. $200pm$
• B. $\frac{\sqrt{3}}{\sqrt{2}}pm$
• C. $142.2pm$
• D. $\sqrt{2}pm$

Answer 1

The correct option is A $200pm$

For BCC,
$Z=2$
$\text{Distance of closest approach}=\frac{\sqrt{3}a}{2}=1.73\stackrel{\circ }{A}$
$a=2\stackrel{\circ }{A}$
$a=200pm$