Iodine oxidation number

In reaction (19) the iodine shown on the left has an oxidation number of zero. After the reaction, some of the iodine atoms have oxidation number +5 and some —1. In other words, the iodine oxidation number has gone both up and down in the reaction. This is an example of selfoxidation-reduction, sometimes called disproportionation. It is a reaction quite typical of, but not at all restricted to, the halogens. 

A redox reaction the chlorine oxidation number decreases from zero to -1 the bromine or iodine oxidation number increases from -1 to zero. 

Identify the oxidation number of the halogen atoms in (a) iodine heptafluoride (b) sodium periodate (c) hypobromous acid (d) sodium chlorite. 

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 ... 

EXAMPLE 13.1. What are the oxidation numbers of chlorine and iodine in ICl, ... 

Example What is the oxidation number of iodine in the following species I2,1 , Mgl2, ICI3, IO3... 

Step 3 Iodine is the element that undergoes an increase in oxidation number. Oxygen is the element that undergoes a decrease in oxidation number. 

Step 4 Iodine undergoes an increase in its oxidation number from... 

Step 5 A 2 1 ratio of iodine atoms to oxygen atoms ensures that the total increase in oxidation numbers and the total decrease in oxidation numbers are both equal to 2. This is the smallest whole-number ratio. 

The oxidation number of iodine in IQ2 is +1. This is unusual, because halogens are usually — 1. However, because chlorine is more electronegative than iodine, we assign Cl as — 1, thereby forcing I to be +1. 

The oxidation numbers are assigned above. Note that chlorine has an oxidation number of — 1 on both sides of the equation. Only iodine is involved in electron transfer. 

PROBLEM 4.12 Aqueous copper(II) ion reacts with aqueous iodide ion to yield solid copper iodide and aqueous iodine. Write the balanced net ionic equation, assign oxidation numbers to all species present, and identify the oxidizing and reducing agents. 

The purpose of present review is to summarize the application of different classes of iodine(III) compounds in carbon-carbon bond forming reactions. The first two sections of the review (Sects. 2 and 3) discuss the oxidative transformations induced by [bis(acyloxy)iodo] arenes, while Sects. 4 through 9 summarize the reactions of iodonium salts and ylides. A number of previous reviews and books on the chemistry of polyvalent iodine discuss the C-C bond forming reactions [1 -10]. Most notable is the 1990 review by Moriarty and Vaid devoted to carbon-carbon bond formation via hypervalent iodine oxidation [1]. In particular, this review covers earlier literature on cationic carbocyclizations, allyla-tion of aromatic compounds, coupling of /1-dicarbonyl compounds, and some other reactions of hypervalent iodine reagents. In the present review the emphasis is placed on the post 1990s literature. 

For group VIIA atoms, the oxidation numbers of chlorine (Cl), bromine (Br), and iodine (I) are -1 except when they combine with oxygen (O) or Fluorine (F). 

C) Chlorite-iodine species-reductant. Several subclasses may be distinguished within this category according to the oxidation number of the iodine species involved ... 

As with the other halogens, iodine is a diatomic molecule. It is always found in nature in a combined state, often as iodide salts where it has a -1 oxidation number. Compounds in which iodine is found to have oxidation numbers of 7, 3, 5, and 1 are also well known. Iodine is prepared commercially by treatment of natural salt solutions (seawater or brines) with chlorine (a more reactive halogen), according to the reaction ... 

The oxidation number of iodine changes from — 1 to 0. Iodide ions are mostly added in the form of potassium iodide KI. Reductions with I- are e.g. ... 

Because fluorine in its compounds exhibits only a negative oxidation number, the iodine must have positive oxidation numbers in all four compounds. It can exhibit a 4-7 oxidation number (its maximum), as well as 4-5, 4-3, and 4-1 (steps of 2). The formulas are therefore IF7, IF5, IF3, and IF. 

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