Periodinane

Periodinanes are chemical compounds containing hypervalent iodine. These iodine compounds are hypervalent because the iodine atom in it contains more than the 8 electrons in the valence shell required for the octet rule. When iodine is complexed with a monodentate electronegative ligand such as chlorine, iodine compounds occur with a +3 oxidation number as iodine(III) or λ-iodanes or as a +5 oxidation number as iodine(V) or λ-iodanes. Iodine itself contains 7 valence electrons and in a λ-iodane three more are donated by the ligands making it a decet structure. λ-iodanes are dodecet molecules. In an ordinary iodine compound such as iodobenzene the number of valence electrons is eight as expected. In order to get from iodine to a hypervalent iodine compound it gets oxidized with removal of first 3 electrons and then 5 electrons. The ligands in turn contribute electrons pairs and form coordinate covalent bonds by adding a total of 6 or 10 electrons back to iodine. In the L-I-N notation L stands for the number of electrons donated by ligands and N the number of ligands.