Interhalogen

Beyond that, iodine monochloride has several applications, including helping to measure the saturation of fats and oils, and as a catalyst for some reactions.

[1] Similar compounds exist with various pseudohalogens, such as the halogen azides (FN3, ClN3, BrN3, and IN3) and cyanogen halides (FCN, ClCN, BrCN, and ICN).

The interhalogens of form XY have physical properties intermediate between those of the two parent halogens.

The covalent bond between the two atoms has some ionic character, the less electronegative halogen, X, being oxidised and having a partial positive charge.

All combinations of fluorine, chlorine, bromine, and iodine that have the above-mentioned general formula are known, but not all are stable.

[11][12] In addition, there exist analogous molecules involving pseudohalogens, such as the cyanogen halides.

All stable hexatomic and octatomic interhalogens involve a heavier halogen combined with five or seven fluorine atoms.

Unlike the other halogens, fluorine atoms have high electronegativity and small size which is able to stabilize them.

[1] Interhalogens with one or three halogens bonded to a central atom are formed by two elements whose electronegativities are not far apart.

Interhalogens with five or seven halogens bonded to a central atom are formed by two elements whose sizes are very different.

The bond length of interhalogens in the XY series increases with the size of the constituent halogens.

ClF and BrF can both be produced by the reaction of a larger interhalogen, such as ClF3 or BrF3 and a diatomic molecule of the element lower in the periodic table.

Among the hexatomic interhalogens, IF5 has a higher boiling point (97 °C) than BrF5 (40.5 °C), although both compounds are liquids at room temperature.