Question

What is the use of radius ratios?

• A. It helps us determine whether a material is crystalline or amorphous.
• B. It helps determine the coordination number of a crystal.
• C. It helps determine the types of voids present in a crystal.
• D. It helps estimate the number of atoms in a crystal.

Answer 1

Answer: (B), (C)

The correct options are
B

It helps determine the coordination number of a crystal.

C

It helps determine the types of voids present in a crystal.

Radius ratio is one of the most important concepts we learn in solid state because it helps us determine coordination number of any given crystal. The value of the radius of any given anion or cation can be calculated by experiments and we can actually predict the coordination of the crystal with this information (but this is not always true. It only works 50% of the time). It can also help us estimate type of voids in a crystal.