Oxidation combined halogen atom

Second, in Rule 5, note that the -1 oxidation number for a combined halogen atom is strictly limited to binary compounds with a metal or hydrogen. Halogens found in polyatomic ions or in ternary compounds do not have an oxidation number of-1. Third, Rules 8 and 9 mentions peroxides. Peroxide is a polyatomic ion that consists of two oxygen atoms that have a net charge of -2, or... 

The oxidation number of every halogen atom in its compounds is - 1 except for a chlorine, bromine, or iodine atom combined with oxygen or a halogen atom higher in the periodic table. For example, the chlorine atoms in each of the following compounds have oxidation numbers of -1 ... 

Binuclear oxidative additions, because they involve le rather than 2e changes at the metals, often go via radicals. One of the best known examples is shown in Eq. 6.21. The rate determining step is abstraction of a halogen atom from RX by the d Co(II) the resulting R combines with a second Co(II) center ... 

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