Question

What is the difference between an amorphous solid and a crystalline solid on the macroscopic and molecular levels? Give an example of each.

Short answer

A crystalline solid has an organized structure in which the constituent atoms/ions are packed in three-dimensional structures whereas an amorphous solid has a comparatively less ordered structure in a 3-D framework.

On a macroscopic level, the crystalline structure has a definite structure whereas the amorphous solid does not have any characteristic shape.

Examples of crystalline and amorphous solids are $\mathbf{NaCl}$crystal and glass respectively.

Step-by-step solution

Molecular level difference

On the molecular level, the crystalline solid has all its constituent atoms/ions arranged in a proper orientation known as unit cells whereas an amorphous solid have a comparatively random sequence of atomic entities.

When examined by X-rays, the crystalline solids show sharp diffraction peaks whereas the peaks are broadened in amorphous solids.

Macroscopic difference

Crystalline solids are very rigid crystals and due to their molecular arrangement shows anisotropic behavior whereas the amorphous solids do not have any characteristic shape due to the random arrangement, thus isotropic in nature.

Examples

Crystalline solids example: NaCl, ZnS, ${\mathbf{CaF}}_2$, etc.

Amorphous solids example: Glass, rubber, polymers, etc.