Question

define a primitive cell ? can a unit cell be permitted?

Answer 1

the smallest possible unit of a lattice ,having lattice points at each of its 8 vertices only

Answer 2

Answer:

In geometry, biology, mineralogy, and solid state physics, a primitive cell is a unit cell corresponding to a single lattice point of a structure with discrete translational symmetry. ... The volume of the conventional cell is always an integer multiple (typically 1, 2, 3, or 4) of the primitive cell volume.