Question

The two ions $A^{+}$and $B^{-}$have radii $88$ and $200pm$ respectively. In the closed packed crystal of compound $AB$, Predict the co-ordination number of $A^{+}$.

Answer 1

Answer: 6.00

$\frac{r_{+}}{r_{-}}=0.44$
Since, $0.414<\frac{r_{+}}{r_{-}}<0.732$
$A^{+}$occupies octahedral void
$\Rightarrow CNo.=6$