In a multi layered close-packed structure

In a closed packed structure

How are spheres arranged in first layer of cubic close-packed structures? How are successive layers of spheres placed above this layers?

Coordination number in a square close packed structure and hexagonal close packed structure respectively are

Why a hexagonal close-packed structure and a cubic close-packed structure for a given element would be expected to have the same density?

Why a hexagonal close-packed structure and a cubic close-packed structure for a given element would be expected to have the same density?

Why a hexagonal close-packed structure and a cubic close-packed structure for a given element would be expected to have the same density?

Calculate the packing fraction in a hexagonal close-packed structure with similar particles.

In a hexagonal close packed (hcp) structure of spheres, the fraction of the volume occupied by the sphere is A. In a cubic close packed structure the fraction is B. The relation for A and B is: