Interstitial sites

Definition

Interstitial sites are positions within a crystal lattice where atoms or ions can reside that are not part of the regular lattice points. These sites are typically smaller and often occupied by smaller atoms or ions.

5 Must Know Facts For Your Next Test

1. Interstitial sites can significantly influence the properties of materials, such as their electrical conductivity and mechanical strength.
2. Common types of interstitial sites include tetrahedral and octahedral voids in close-packed structures.
3. The size and shape of an interstitial site determine which atoms or ions can fit into them without distorting the crystal lattice.
4. Interstitial impurity atoms often cause lattice strains, leading to changes in the material's physical properties.
5. In metals, interstitials are usually occupied by small atoms like hydrogen, carbon, or nitrogen.

Review Questions

• What are interstitial sites and how do they differ from regular lattice points?
• Name two types of interstitial sites commonly found in close-packed crystal structures.
• How do interstitial impurity atoms affect the properties of a solid?

Related terms

Crystal Lattice: A three-dimensional arrangement of atoms, ions, or molecules in a crystalline material.

Tetrahedral Voids: Small spaces within a crystal structure formed by four surrounding atoms or ions creating a tetrahedron shape.

Octahedral Voids: Larger spaces within a crystal structure formed by six surrounding atoms or ions creating an octahedron shape.