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chemistry/hexagonal-close-packing
View PricingHexagonal Close Packing
Explore the hexagonal close-packed structure in metallic crystals. Understand A-B layer stacking, the hexagonal unit cell, and coordination number.
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Key Concepts
Hexagonal Close Packing (HCP)
Atoms stacked in A-B-A-B close-packed layers, achieving 74.05% space efficiency.
Coordination Number 12
Each atom has 12 nearest neighbors: 6 in the same layer, 3 above, and 3 below.
Hexagonal Unit Cell
A primitive hexagonal prism containing 6 atoms (2 formula units).
Understanding Hexagonal Close Packing
**Hexagonal Close Packing (HCP)** is a dense atomic arrangement where atoms occupy 74.05% of the total volume, shared by metals such as Magnesium (Mg), Zinc (Zn), and Titanium (Ti).
The structure is characterized by an alternating **A-B-A-B** stacking sequence of close-packed hexagonal layers, where atoms in the third layer are positioned directly above the atoms in the first layer.
Our interactive crystal viewer demonstrates the **coordination number of 12** and visualizes the geometric relationship between the hexagonal close-packed layers and the primitive hexagonal prism unit cell.
Frequently Asked Questions
Related Simulations
Cubic Close Packing
**Cubic Close Packing (CCP)** is a high-efficiency crystal structure where atoms are arranged in an **A-B-C** stacking sequence. This resource visualizes the **Face-Centered Cubic (FCC)** unit cell and its 74.05% packing efficiency.
Tetrahedral Voids
A **Tetrahedral Void** is the interstitial space surrounded by four atoms in a tetrahedral arrangement. This resource locates the eight tetrahedral voids within a **Face-Centered Cubic (FCC)** unit cell.
Octahedral Voids
An **Octahedral Void** is the interstitial space surrounded by six atoms in an octahedral arrangement. This resource visualizes the position and count of these voids within a **Face-Centered Cubic (FCC)** lattice.