Solid iodine is an example of a molecular solid.

Explanation:
Molecular solids are composed of individual molecules held together by intermolecular forces. In the case of solid iodine, it consists of diatomic iodine molecules (I2) held together by weak van der Waals forces.

Intermolecular forces:
Intermolecular forces are the attractive forces between molecules. They are weaker than chemical bonds but still play a crucial role in determining the physical properties of substances.

Van der Waals forces:
Van der Waals forces are the intermolecular forces that occur between non-polar or weakly polar molecules. These forces arise from temporary fluctuations in electron distribution, leading to temporary dipoles that induce dipoles in neighboring molecules.

Solid iodine:
Solid iodine exists as a lattice of I2 molecules held together by van der Waals forces. Each iodine molecule consists of two iodine atoms covalently bonded together. These molecules are held together in a regular arrangement to form a crystal lattice.

Properties of solid iodine:
1. Appearance: Solid iodine is a shiny, dark purple crystalline solid.
2. Melting and boiling points: Solid iodine has a melting point of 113.7°C and a boiling point of 184.4°C.
3. Solubility: Solid iodine is sparingly soluble in water but dissolves readily in organic solvents like ethanol and chloroform.
4. Electrical conductivity: Solid iodine is a poor conductor of electricity because the iodine molecules are electrically neutral and do not contain free ions or delocalized electrons.

Conclusion:
Solid iodine is classified as a molecular solid because it consists of individual I2 molecules held together by weak van der Waals forces. Understanding the different types of solids helps in explaining their physical properties and behavior.