In a multilayered close - packed stracture

In a multi layered close-packed structure

In a multi layered close-packed structure

In a closed packed structure

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

How do you distinguish between hexagonal close - packing and cubic close - packing structures ?

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?

In two dimensions, which one represents the close-packed structure of spheres with highest packing efficiency, a square close-packing or a hexagonal close-packing? Explain in it terms of coordination number of sphere in each case.