What are interhalogen compounds 2

LP Georg-August-University Goettingen

Interhalogen compounds

In addition to the halogen-hydrogen compounds and the halides, which we will get to know later, there are the interhalogen compounds. These are compounds that are built up exclusively from halogen atoms. Let's consider the following reaction:

In this reaction, X is a heavy halogen. So far, the following uncharged species are known: In addition to the uncharged interhalogen compounds, the polyhalide ions also exist. Interhalogen compounds are always charged when an even number of halogen atoms are bonded to the central atom. They therefore use the general empirical formula or. .
In the following we want to consider how we can represent the interhalogen compounds. Let's start with the simplest type of class . To do this, elemental iodine simply has to be reacted with the elemental halogen to form an interhalogen compound that contains iodine. This reaction takes place at room temperature:
If we convert elemental chlorine with elemental fluorine at 225 ° C, we can receive. However, the product also contains . If this is reacted with elemental chlorine at 300 ° C, this also results

Interhalogen compounds of the type can only be synthesized from the elements with suitable reaction compounds. For this reason, elemental iodine is reacted with xenon difluoride for iodine trifluoride, for example. In addition to the desired product, elementary xenon is also produced.
The connections of the type are difficult to make from the elements. For the preparation of chlorine pentafluoride from fluorine and chlorine, 350 ° C and 250 bar pressure are required. The reaction of chlorine trifluoride with fluorine, on the other hand, can take place at room temperature and one bar pressure. Energy in the form of light is sufficient to activate the reaction. Bromopentafluoride can be produced from the potassium salt of bromine and elemental fluorine. This reaction also takes place at 25 ° C.

As already seen, the type exists just the connection . This can be synthesized at 300 ° C from the elements or from palladium (II) iodide and elemental fluorine.