Interhalogen compounds iodine pentafluoride

Fluorine also reacts with other halogens, forming interhalogen compounds. While with bromine and iodine it reacts vigorously at ordinary temperatures, with chlorine the reaction occurs at 200°C. Such interhalogen products with these halogens include iodine heptafluoride, bromine trifluoride, bromine pentafluoride, and chlorine trifluoride. Metalloid elements, such as arsenic, silicon, selenium, and boron also inflame in a stream of fluorine, forming fluorides. 

The electronic configuration of halogens shows that there are seven electrons in the outermost shell of these atoms. Thus the most common valence state is 1. Although uncommon, halogens exhibit higher valencies, too, especially in interhalogen compounds. For example, in bromine pentafluoride and iodine heptafluoride, bromine and iodine exhibit valencies of 5 and 7, respectively. 

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