Question

What is the packing efficiency of fcc crystal structure?

• A. 74.0 %
• B. 68.04 %
• C. 52.4 %
• D. 47.6 %

Hint:

Packing efficiencies: fcc = 74%, hcp = 74%, bcc = 68%, sc = 52%.

Answer 1

The Correct Option is A

Step 1: Recall packing efficiency.
Packing efficiency is the fraction of the total volume of the unit cell that is actually occupied by the constituent particles (atoms/ions).

Step 2: fcc crystal characteristics.
In a face-centered cubic (fcc) unit cell:
Number of atoms per unit cell \(= 4\).
Atoms touch along the face diagonal.

Step 3: Standard result.
For fcc structure, the packing efficiency has a well-known calculated value of \(\approx 74%\).

Step 4: Conclusion.
The packing efficiency of an fcc crystal structure is \(74.0%\).