Question

Which of the following structures has the highest density of packing?

• A. Diamond cubic
• B. Cesium chloride
• C. Body centred cubic
• D. Face centred cubic

Hint:

FCC and HCP structures have the highest packing efficiency (74%), while BCC and diamond cubic structures are less densely packed.

Answer 1

The Correct Option is D

The packing density of a crystal is determined by its packing efficiency, which represents the fraction of the unit cell volume that is occupied by atoms. The packing efficiencies for the given structures are: - Diamond cubic: 34% (due to tetrahedral arrangement) - Cesium chloride (CsCl): 68% (similar to simple cubic) - Body-centered cubic (BCC): 68% (moderate packing efficiency) - Face-centered cubic (FCC): 74% (highest packing efficiency) Conclusion: FCC has the highest packing efficiency of 74%, making it the most densely packed structure among the given options.