Precipitation and Crystallization (Macro Cohesion)

IMFs involved: Ion–dipole, hydrogen bonding, π–π stacking, van der Waals, electrostatic Why common: Precipitation is a standard separation/purification method; crystallization is central to pharmaceutical, materials, and geological chemistry. Co-crystal formation is a major IMF-driven reaction class.

Examples:

• Ag⁺ + Cl⁻ → AgCl(s) (precipitation from aqueous solution)
• Ba²⁺ + SO₄²⁻ → BaSO₄(s)
• Pharmaceutical co-crystals (e.g., carbamazepine–nicotinamide via H-bonding)
• Protein crystallization (hydrophobic + H-bonding + electrostatic)
• Salt formation (acid + base → ionic solid)
• Ice crystallization (H-bonding)
• Mineral precipitation (CaCO₃, etc.)

Role of IMFs: Desolvation and lattice formation are driven by H-bonding, ion–dipole, π–π, and van der Waals; co-crystals are held together entirely by IMFs.