Question

How many atoms of an element are there in one unit cell of body-centred cubic?

Answer 1

The cubic unit cell in body-centred cubic systems consists of eight atoms at each corner and one in the centre. The corner atoms contribute 1/8 and the body centre atoms contribute 1 to the unit cell, and each corner atom is shared equally by eight unit cells. 

∴ Number of atoms in a body-centred unit cell 

= `(8 xx 1/8) + 1`

= 1 + 1

= 2 atoms

Thus, the unit cell of a body-centred cubic system contains 2 atoms.