In an unsaturated solution, ions are dispersed throughout the solvent by repulsive force and exist as separate entities. However, in a saturated solution, ions will precipitate out as large flakes of metallic silver particles as the solution cools. These flakes are usually flat and can grow to a very large size, up to 0.100 inches in diameter, and drop to the bottom. In a saturated solution, silver ions will recover an electron from an anion as they precipitate to metallic silver. When a silver ion receives an electron from an anion during cooling of a saturated solution, the ion becomes a silver atom. Silver atoms have no ionic charge to produce a repulsive force, so they are drawn together by the van der Waals’ force of attraction and aggregate into particles of metallic silver. The predominate anions in a silver ionic solution are carbonate and hydroxide. If the anion providing the electron is a carbonate, carbonic acid is formed which lowers the pH of the solution during this process.
Colloidal Silver | Silver Colloids
