Question

If lattice parameter for a crystalline structure is $3.6\mathring{A}$, then atomic radius in fcc crystal in $\mathring{A}$ is :

• A. $7.20$
• B. $1.80$
• C. $1.27$
• D. $2.90$

Answer 1

The correct option is C $1.27$

Atomic radius of fcc crystal is :

$r=\frac{a}{2\sqrt{2}}$

$=\frac{3.6}{2\sqrt{2}}=1.27\stackrel{\circ }{A}$