Question

The lattice constant of the unit cell of α iron is 0.285 nm. Find the number of atoms/mm2 of the (100) plane. The α iron has bcc structure.

Answer 1

As shown in the figure in plane ( 1 0 0) there are 4 atoms at corner and 1 atom at center.

each of the atom at corner will contribute 1/8

hence no. of atoms at corner 4*1/8 = 0.5 atom at corner

if we include center atom also

so there will be 3.5 atoms.