Question

The ionic radii of Rb⁺ , Br^– are 1.47 and 1.95 respectively. Predict the most probable type of geometry exhibited by RbBr on the basis of radius ratio rule. 

Answer 1

Given: Radius of Cation Rb⁺ (r⁺ ) = 1.47Å 

 Radius of anion Br^– (r^– ) = 1.95 Å 

To find: Structure of RbBr = ? 

Formula:  

Radius ratio = Radius of the cation/Radius of the anion

Calculation: 

From formula,

Radius ratio

Since the radius ratio lies in between 0.732 – 1.0 

The coordination number of RbBr is 8 

And the structure of RbBr is Cubic.