Chemistry - Solid State Question with Solution | TestHub

In$\mathrm{N}\mathrm{a}\mathrm{C}\mathrm{l}$type of arrangement anion occupies corner of unit cell and and cation in octahedral void at edge center.
Length of unit cell$\left(\mathrm{a}\right)\mathrm{}=2{\mathrm{r}}^{-}+2{\mathrm{r}}^{+}$
Surface diagonal is,
$4{\mathrm{r}}^{-}=\sqrt{2}\mathrm{a}\mathrm{}$(given$\mathrm{\alpha }=5.14\mathrm{}\mathrm{\AA }$)
${\mathrm{r}}^{-}=\sqrt{2}\mathrm{}\mathrm{a}/4\mathrm{}=\frac{1.414\times 5.14}{4}=1.815\mathrm{\AA }$