Question

Copper has an fcc crystal structure. Assuming an atomic radius of 130 pm of a Cu atom, what is the length of its unit cell?
Use: $\sqrt{2}=1.41,\sqrt{3}=1.73$.

• A. 366.6 pm
• B. 92.20 pm
• C. 300.6 pm
• D. 183.3 pm

Answer 1

The correct option is A 366.6 pm

For fcc structure,
$4r=\sqrt{2}a$ or, $a=2\sqrt{2}r=2\sqrt{2}\times 130=366.6$ pm