interhalogen

Interhalogen compounds are chemical species composed of two or more different halogen elements, such as fluorine (F), chlorine (Cl), bromine (Br), and iodine (I). They are typically covalent molecules or ions formed by the reaction of halogens with one another and exhibit a range of stoichiometries, commonly written as XY, XY3, XY5, or XY7, where X and Y are halogens. The bonds are highly polarized due to differences in electronegativity, making many interhalogens good oxidizing and halogenating agents.

Representative interhalogen compounds include ClF, BrCl, ICl, BrF3, ClF3, BrF5, IF5, and IF7. These species vary in geometry and stability; for example some tri- and pentahalogen compounds adopt T-shaped, square-pyramidal, or pentagonal-bipyramidal structures. They are typically highly reactive, volatile, and often sensitive to moisture.

Preparation and handling usually involve controlled halogen halogen reactions, carried out under inert atmosphere or selective conditions to avoid decomposition. Interhalogens are used as reagents in inorganic and organic synthesis because they can transfer halogen atoms or deliver halogenating power in a single step. They may also serve as sources of halogen under laboratory conditions, or as intermediates in the production of more reactive fluorinating or chlorinating agents.

Safety and storage considerations are important, as interhalogen compounds are strong oxidizers, corrosive, and toxic. They react vigorously with water to form halogen acids and oxygen-containing byproducts, and proper containment, ventilation, and corrosion-resistant materials are required in their handling.