Question

AB is an ionic solid. If the ratio of ionic radii of $ {{\text{A}}^{\text{+}}} $ and $ {{\text{B}}^{-}} $ is 0.52, what is the coordination number of $ {{\text{B}}^{-}} $ ?

• A. 2
• B. 3
• C. 6
• D. 8

Answer 1

Answer: (C)

Radius ratio $ {{r}^{+}}/{{r}^{-}} $
Coordination number
0.155-0.225
3
0.225-0.414
4
0.414-0.732
6
0.732-1.00
8
Hence, if the ratio of ionic radii is 0.52, then the coordination number of $ {{B}^{-}} $ is 6.