Question

Difference between primitive cell and unit cell and seitz primitive cell

Answer 1

primitive cell :it allows latice points only at the corners of a cells.
2.it is not unique.
3.conventionally a primitive cell is choosen the cell with smallest primitive vectors.

unit cell : it allows lattice point at corner,face centers and body center.
2.it is unique.
3.unit cell can be used instead of primitive cells in cases where it can reperesent better lettice.

seitz cell :here is a special type of primitive-cells known as Wigner-Seitz cell. 
2.he Wigner-Seitz cell of a lattice point is defined as the volume that encloses all points in space which are closer to this particular lattice point than to any other.