The ionic radii of , , and are , , and respectively. What is the coordination number of the cation i — Solid State Chemistry Question

💡 Solution & Explanation

The radius ratio for $KBr$ is $\frac{r_{K^+}}{r_{Br^-}} = \frac{138}{195} \approx 0.707$. Because this ratio falls within the $0.414$ to $0.732$ limiting range, the $K^+$ ion fits into an octahedral void, resulting in a coordination number of 6.