Two interhalogens having strong disinfecting properties are iodine monochloride (IC1) and iodine bromide (IBr). Iodine monochloride has found use as a topical antiseptic. It may be complexed with nonionic or anionic detergents to yield bactericides and fungicides that can be used in cleansing or sanitizing formulations. These generally have a polymer structure which establishes its great stability, increased solubility, and lower volatility. By reducing the free halogen concentration in solution, polymers reduce both the chemical and bactericidal activity. Complexes of IC1 are useful disinfectants which compromise lower bactericidal activity with increased stability. Iodine monochloride is itself a highly reactive compound, reacting with many metals to produce metal chlorides. Under normal conditions it will not react with tantalum, chromium, molybdenum, zirconium, tungsten, or platinum. With organic compounds, reactions cause iodination, chlorination, decomposition, or the generation of halogen addition compounds. In water, ICI hydrolyzes to hypoiodous and hydrochloric acids. In the absence of excess chloride ions, hypoiodous acid will disproportionate into iodic acid and iodine. Iodine bromide has a chemistry similar to ICI. Iodine bromide reacts with aromatic compounds to produce iodination in polar solvents and bromination in nonpolar solvents. It has complex chemical properties, as its solubility is increased more effectively by bromide than by chlorided ions. Primary hydrolysis takes place in the presence of hydrobromic acid. As a disinfectant, IBr is used in its complexed or stabilized forms. Unfortunately, it undergoes hydrolysis and dissociation reactions in aqueous solutions, both reactions being major limitations. Its disinfecting properties are similar to ICI and as in the case of ICI, germicidal activity should not be reduced by haloamine formation since bromamines are highly reactive and iodoamines are not generated. Upon application of prepared solutions to control microorganisms, the complex releases IBr gradually. This process forms free iodine during the decomposition of IBr (the decomposition takes place as fast as the IBr is released).
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