Deionized water is water that has had its mineral ions removed, such as sodium, calcium, iron, and copper. This process is typically achieved through ion exchange, where charged particles are replaced with hydrogen and hydroxide ions. The result is highly purified water that is free from dissolved salts and impurities. Deionized water is commonly used in laboratories, industrial processes, and electronics manufacturing, where the presence of minerals can interfere with experiments or product quality. It is also used in aquariums and steam irons to prevent mineral buildup.