Crystal Structure

Materials are categorized into 2, based on the arrangement of atoms or molecules.

• Crystalline
• Amorphous

Crystalline

Atoms or molecules are arranged in a ordered structure. Long-order is present. Situated in a repeating array over large atomic distances (long-range order).

Examples:

• Metals
• Ceramics

Atomic arrangement is usually described by space lattice.

Amorphous (or Non Crystalline)

Atoms or molecules are randomly arranged. Long-range order is absent.

Example:

• Glass
• Polymers are semi-crystalline