Chemical Tips Sharing – Halogen Interhalides

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Binary compounds formed by the sharing of electron pairs between different halogen atoms are called halogen interhalides. Use XX′n to denote (n=1, 3, 5, 7). The electronegativity of X′ is greater than that of X. The most common ones are the halogen interhalides of fluorine, such as ClF, ClF3, IF5, IF7, etc. Their molecular geometries in space are linear, T-shaped, tetrahedral pyramidal, and pentagonal bipyramidal, respectively. The physical properties of halogen interhalides are similar to those of elemental halogens; they have different colors and states, as well as low melting and boiling points. Their chemical properties are generally more reactive than those of halogen elements (except F2). The vast majority of unstable substances are strong oxidizers that can react violently with most metals and non-metals to form corresponding halides. XX′, XX′3, and XX′5 are prone to hydrolysis to yield halide ions and haloxy ions. For example, XX′+H2O=H++X′+HXO. Iodine heptafluoride is more stable than other fluorine interhalides, and it slowly hydrolyzes in water to yield hypiodic acid and fluoride ions. Fluoride interhalides can convert metals, metal oxides, and metal chlorides, bromides, and iodides into fluorides, and are commonly used as fluorinating agents. Under certain conditions, halogen interhalides can be directly synthesized using elemental halogens. For example,