Question

Ni crystallize s in a face - centered cubic structure. The radius of nickel atom is 1.25 A°.

What is the length of the unit cell edge in angstrom?

Answer 1

Let length of unit cell edge =a

Diagonal= 4r, where r is radius of the

atom

$a^2+a^2=( 4r)^2$

$a=2r\sqrt2$

$a=2×1.25×√2$

$=3.53553\text{\AA}$