The effective number of lattice points in the unit cell

The effective number of lattice points in the unit cell of simple cubic, body centered cubic, and face centered cubic space lattices, respectively, are

For a simple cubic unit cell:
8 corners have 8 atoms and each atom at one corner contributes to 8 unit cells.
Effective number

= 8 ×	1	= 1
	8

For Body centred cubic,
Effective number = 8 corners + 1 centre

= 8 ×	1	+ 1 = 2
	8

For Face centered cubic,
effective number = 8 corner + 6 faces

= 8 ×	1	+ 6 ×	1	= 1 + 3 = 4
	8		2

Therfore, answer is (1, 2, 4)