💡 The body center octahedral void is surrounded by 6 face-centered atoms forming a regular octahedron.
Octahedral Voids in an FCC Unit Cell
Locate octahedral voids in an FCC crystal, understand their geometry, and connect them to NaCl-type structures.
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Key Concepts
Octahedral Coordination
An octahedral void is surrounded by 6 atoms, giving a coordination number of 6.
Position & Count in FCC
In an FCC unit cell there are 4 octahedral voids: 1 at the body center and 12 at edge centers shared by 4 cells.
Crystal Examples
NaCl is a classic structure where the anions form an FCC lattice and the cations occupy all octahedral voids.
Understanding Octahedral Voids
Octahedral Voids are the interstitial spaces in a crystal lattice surrounded by six nearest-neighbor atoms. In a Face-Centered Cubic (FCC) unit cell, these voids are systematically positioned at the body center and at the center of each of the twelve edges.
The geometry of an octahedral void is defined by a coordination number of 6. Each FCC unit cell contains a total of four octahedral voids (1 body-center void + 12 × 1/4 edge-center voids), matching the number of lattice atoms per cell.
Explore our interactive model to visualize how iconic structures like Sodium Chloride (NaCl) are assembled, where larger ions form the FCC framework while smaller ions occupy all available octahedral voids.
Frequently Asked Questions
Related Simulations
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.
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.
Hexagonal Close Packing
**Hexagonal Close Packing (HCP)** is a high-efficiency crystal structure with an **A-B-A-B** stacking sequence. This resource explores the **Hexagonal Unit Cell** and its 74.05% packing density.