Crystalline solids

Definition

Crystalline solids are materials whose atoms, ions, or molecules are arranged in a highly ordered, repeating pattern extending in all three spatial dimensions. They exhibit distinct melting points and characteristic geometric shapes.

5 Must Know Facts For Your Next Test

1. Crystalline solids have long-range order, meaning their atomic structure repeats periodically over large distances.
2. They can be classified into different types based on the nature of their bonding: ionic, covalent, metallic, and molecular crystals.
3. The arrangement of particles in crystalline solids can be described by a lattice system; common examples include cubic, tetragonal, and hexagonal lattices.
4. X-ray diffraction is a primary method used to determine the structure of crystalline solids.
5. Crystalline solids exhibit anisotropic properties, meaning their physical properties vary depending on the direction of measurement within the crystal.

Review Questions

• What distinguishes crystalline solids from amorphous solids?
• How are crystalline solids classified based on bonding types?
• Describe how X-ray diffraction is used to study crystalline solids.

Related terms

Amorphous Solids: Solids that lack a well-defined long-range order in their atomic or molecular arrangement.

Unit Cell: The smallest repeating unit of a crystal lattice that shows the entire structure's symmetry.

Polymorphism: The ability of a solid material to exist in more than one form or crystal structure.