Highest oxidation states

Elements exhibit their highest oxidation state when combined with fluorine. 

Fluorine is the most electronegative element and thus can oxidize many other elements to their highest oxidation state. The small size of the fluorine atom facihtates the arrangement of a large number of fluorines around an atom of another element. These properties of high oxidation potential and small size allow the formation of many simple and complex fluorides in which the other elements are at their highest oxidation states. 

Metal—Metal Bonding. The degree of nuclearity exhibited as a function of the oxidation state of molybdenum is shown in Table 1. In the highest oxidation state, Mo(VI), the tendency is to form mononuclear or a wide variety of polynuclear complexes in which there are no... 

Transition metals can be divided into two groups according to the characteristics of their peroxides. The first group comprises those metals that, in their highest oxidation states, have no d electrons, eg, TP" and These metals form peroxides from hydrogen peroxide, the colors of which result from... 

No entirely satisfactory explanation of these observations has been devised, though they are paralleled by the similar reluctance of other elements following the completion of the 3d subshell to achieve their highest oxidation states — see particularly Se (p. 755) and As (p. 552) immediately preceding Br in the periodic table. The detailed kinetics of several oxidation reactions involving aqueous solutions of Br04 ... 

In moving across the transition series, iron is the first element which fails to attain its group oxidation state (-1-8). The highest oxidation state known (so far) is 4-6 in [Fe04] and even this is extremely easily reduced. On the... 

This half-reaction occurs when the anion cannot be oxidized. Examples include nitrate and sulfate anions, where the nonmetal present is already in its highest oxidation state (+5 for N, +6 for S). 

To devise a periodic table of configurations of bonded atoms we would be obliged to focus on perhaps the highest oxidation state or the lowest oxidation state. Such decisions would not appear to... 

Since the sulphone group contains sulphur in its highest oxidation state, specific analytical procedures based on controlled oxidation are not possible. The complete molecule can be submitted to oxidative degradation, e.g. in the elemental sulphur determination, methods for which, as stated above, will not be included here. 

On the basis of these facts, it was speculated that plutonium in its highest oxidation state is similar to uranium (VI) and in a lower state is similar to thorium (IV) and uranium (IV). It was reasoned that if plutonium existed normally as a stable plutonium (IV) ion, it would probably form insoluble compounds or stable complex ions analogous to those of similar ions, and that it would be desirable (as soon as sufficient plutonium became available) to determine the solubilities of such compounds as the fluoride, oxalate, phosphate, iodate, and peroxide. Such data were needed to confirm deductions based on the tracer experiments. 

The radicals, such as methyl, trifluoromethyl, and trifluorosilyl, used in this work have been found to oxidize zero-valent metals to their highest oxidation-state upon cocondensation with these metals on a cold surface at - 196°C. 

The cations in transition metal oxides often occur in more than one oxidation state. Molybdenum oxide is a good example, as the Mo cation may be in the 6-r, 5-r, and 4+ oxidation states. Oxide surfaces with the cation in the lower oxidation state are usually more reactive than those in the highest oxidation state. Such ions can engage in reactions that involve changes in valence state. 

Techniques for attaching such ruthenium electrocatalysts to the electrode surface, and thereby realizing some of the advantages of the modified electrode devices, have been developed.512-521 The electrocatalytic activity of these films have been evaluated and some preparative scale experiments performed. The modified electrodes are active and selective catalysts for oxidation of alcohols.5 6-521 However, the kinetics of the catalysis is markedly slower with films compared to bulk solution. This is a consequence of the slowness of the access to highest oxidation states of the complex and of the chemical reactions coupled with the electron transfer in films. In compensation, the stability of catalysts is dramatically improved in films, especially with complexes sensitive to bpy ligand loss like [Ru(bpy)2(0)2]2 + 51, 519 521... 

The mentioned method for synthesis of oxide-hydroxide compounds (Ni, Cr, Co) is more controllable and enables with production of electrode films definite amounts of components. Therefore it guarantees the reproducibility of their compositions and properties. Using the above method we were able to produce the following oxide compounds zero valence metal and lowest oxidation state oxide-hydroxide compounds in cathode process and oxide-hydroxide compounds (in anode process the oxide compounds consist of highest oxidation state oxide-hydroxide compounds). Both type compounds possesses electronic and ionic conductivity. 

Because the highest oxidation state of Cr is + 6, it forms oxyhalides that have the formula Cr02X2 and are known as chromyl halides. However, in the case of the fluorine compound, CrOF4 is also known, as well as some oxyhalides having the formula CrOX3. Some reactions that yield chromyl halides are the following ... 

Ozone can also be used to transform metals into their highest oxidation states, which is often useful when separation is desired. 

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