Question

Distinguish between hexagonal close packing and cubic close packing. 

Answer 1

Sr. No.	Hexagonal close packing	Cubic close packing
1.	aba arrangement	abc arrangement
2.	In this case, the spheres of the third layer are exactly aligned with those of the first layer.	In this case, the spheres of the third layer are not aligned with those of the first layer or second layer. only when the fourth layer is placed, its spheres are aligned with the first layer.
3.	In HCP, tetrahedral voids of the second layer may be covered by the spheres of the third layer.	In CCP, the third layer may be placed above the second layer in a manner such that its sphere covers the octahedral voids.