Question

Ionic radii of cation $A^{+}$and anion $B^{-}$are 102 and $181pm$ respectively. These ions are allowed to crystallize into an ionic solid. This crystal has cubic close packing for $B^{-}.A^{+}$is present in all octahedral voids. The edge length of the unit cell of the crystal $AB$ is ___$pm$. (Nearest Integer)

Answer 1

Answer: 512

$a=2\left(r_{+}+r_{-}\right)$
$a=2(102+181)$
$a=2(283)$
$a=566pm$