By Michael Judge
Updated Mar 24, 2022
Silver nitrate (AgNO₃) is a classic example of an ionic compound that dissolves readily in water. Upon dissolution, the lattice separates into its constituent ions: the silver cation (Ag⁺) and the nitrate anion (NO₃⁻). This process is driven by the strong electrostatic attraction between the oppositely charged species.
The silver ion carries a single positive charge, having lost one electron. Cations such as Ag⁺ are well‑known for their antimicrobial activity; for instance, a study by the National Public Health Institute of Finland demonstrated that Ag⁺ can effectively inhibit the growth of Legionella bacteria. These properties have led to medical applications, though silver ions remain toxic to a wide range of microbes.
The nitrate ion is a trivalent group consisting of one nitrogen atom bonded to three oxygen atoms, bearing a net negative charge. NO₃⁻ is naturally present in foods like spinach and is a key component of many fertilizers. While essential in moderate amounts, excessive nitrate intake can pose health risks, so its concentration is regulated in food and water supplies.
Even in ultrapure water, trace amounts of ions arise from the auto‑ionization of water molecules:
