Explain how much portin of an atom located at (a) corner and (b) body centre of a cubic unit cell is part of its neighouring unit cell.

Explanation

(i) An atom at the corner is shared by eight adjacent unit cells Hence portion of the atom at the corner that belongs to one unit cell=1/8
(ii) An atom at the body centre is not shared by any other unit cell. Hence it belongs fully to unit cell.