Question

copper which crystallize as a face centered cubic lattice has a density of 8.93 g/cm3 at 20temp c calculate the lengh of unit cell

Answer 1

Answer

For a FCC Lattice, Z=4 and a=2

2

r

Now, Density (ρ)=

a

3

×N

A

Z×M

∴a

3

=

N

A

×ρ

Z×M

∴a

3

=

6.02×10

23

×8.930

4×63.55

∴a

3

=4.728×10

−23

cm

∴(2

2

r)

3

=4.728×10

−23

cm

∴2

2

r=3.616×10

−8

cm

∴r=1.278×10

−8

cm

∴r=1.278

A

∘

Therefore, the radius of copper atom is 1.278

A