Question

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

• A. $2.92\mathring{A}$
• B. $1.27\mathring{A}$
• C. $1.81\mathring{A}$
• D. $2.10\mathring{A}$

Answer 1

The correct option is B $1.27\mathring{A}$

Lattice parameter

$a=\frac{4r}{\sqrt{2}}$

$r=\frac{\sqrt{2}a}{4}=\frac{\sqrt{2}\times 3.6}{4}$

$r=1.27$

Option B is correct.