Question

What do you understand by radius ratio?

What do you understand by radius ratio in ionic solids?

Answer 1

The ratio of the radius of the cation to the radius of the anion is called the radius ratio. Thus,

Radius ratio = `("Radius of cation"  (r_+))/("Radius of anion"  (r_-))`

It is clear from the above relation, greater is the radius ratio, the larger is the size of the cation and greater is its coordination number.