Question

The ionic radii of $A^+$ and $B^-$ ions are $0.98 \times 10^{-10} \, m$ and ${1.81 \times 10^{-10} m}$. The coordination number of each ion in AB is :

• A. 4
• B. 8
• C. 2
• D. 6

Answer 1

The Correct Option is D

Answer: 

6

Explanation:

The coordination number of an ion in a crystal lattice is determined by the ratio of the radii of the cation and anion. The formula to determine the coordination number is given by the radius ratio rule, which relates the ionic radii of the cation and anion in an ionic compound:

The radius ratio is calculated as: \(r_{\text{cation}} / r_{\text{anion}} = \frac{0.98 \times 10^{-10}}{1.81 \times 10^{-10}} \approx 0.54\)

According to the radius ratio rule, for a ratio between 0.414 and 0.732, the coordination number is typically 6. Therefore, the coordination number for both the \(A^+\) and \(B^-\) ions in the compound AB is 6.