Question

A compound $XY$ crystallizes in bcc lattice with unit cell-length of $460pm,$ if the radius of $Y^{\ast }$ is $225pm,$ then the radius of $X^{\ast }$ is:

• A. $190.70pm$
• B. $225pm$
• C. $127.5pm$
• D. None

Answer 1

The correct option is D None

Radius of $X^{+}\Rightarrow r_{+}$

$Y^{-}\Rightarrow r_{-}$

In BCC,

$2(r_{+}+r_{-})=a\sqrt{3}$

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

$r_{+}+225=398.3$

$r_{+}=173.3$ $pm$

Therefore, radius of $r_{+}=173.3$ $pm$