Which of the following minerals is an example of a hexagonal close-packed (HCP) crystal structure?

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Answer 1

Explanation:

Hexagonal Close-Packed (HCP) Crystal Structure:

The hexagonal close-packed (HCP) crystal structure is one of the most efficient ways of packing spheres, where each atom is surrounded by twelve others. In the HCP structure, the atoms are packed closely together in a repeating pattern that forms a hexagonal lattice. This type of structure is characterized by its high density and coordination number, which is 12.

Structure Details:

In the HCP crystal structure, the atoms are arranged in layers. The pattern follows an ABAB stacking sequence where each atom in the 'A' layer is directly above or below an atom in another 'A' layer, while the 'B' layer atoms fit into the depressions of the 'A' layers. This results in a hexagonal unit cell with two atoms per unit cell.

Examples of HCP Structures:

Metals like magnesium (Mg), titanium (Ti), and zinc (Zn) are common examples of elements that crystallize in the HCP structure. Additionally, certain minerals exhibit the HCP structure due to their atomic arrangement.

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