Question

What is the value of radius ratio of ionic crystal having coordination number six?

• A. Greater than 0.732
• B. In between 0.414 to 0.732
• C. In between 0.225 to 0.414
• D. Less than 0.225

Hint:

For coordination number 6, the radius ratio of ionic crystals lies between 0.414 and 0.732.

Answer 1

The Correct Option is B

Step 1: Understanding Radius Ratio for Coordination Number 6.
For ionic crystals, the radius ratio defines the relative sizes of the cation and anion. For a coordination number of six, the radius ratio (r\(_{cation}\)/r\(_{anion}\)) should be between 0.414 and 0.732. This range allows for an efficient packing arrangement in the crystal lattice.

Step 2: Analyzing the options.
(A) Greater than 0.732: Incorrect. This is the range for coordination numbers greater than 6.
(B) In between 0.414 to 0.732: Correct. This is the correct range for the radius ratio for ionic crystals with a coordination number of 6.
(C) In between 0.225 to 0.414: Incorrect. This range corresponds to crystals with lower coordination numbers.
(D) Less than 0.225: Incorrect. This range is not applicable to coordination number 6.

Step 3: Conclusion.
The correct range for the radius ratio of ionic crystals with a coordination number of six is between 0.414 and 0.732, corresponding to option (B).