Single-oxidation-state

Polynuclear transition metal cyanides such as the well-known Prussian blue and its analogues with osmium and ruthenium have been intensely studied Prussian blue films on electrodes are formed as microcrystalline materials by the electrochemical reduction of FeFe(CN)g in aqueous solutionThey show two reversible redox reactions, and due to the intense color of the single oxidation states, they appear to be candidates for electrochromic displays Ion exchange properties in the reduced state are limited to certain ions having similar ionic radii. Thus, the reversible... 

Any positively charged chemical species can be considered a cation or as being in a cationic form. Some will be present as relatively simple, single-oxidation-state cations such as sodium (Na+). Others may be more complex in that they may have several oxidation states such as iron, in either the Fe2+ or Fe3+ states. Cations may also have oxygens or hydroxy groups associated with them, such as FeO+. 

Metals in biological systems function in a number of different ways. Group 1 and 2 metals operate as structural elements or in the maintenance of charge and osmotic balance (Table 1.2). Transition metal ions that exist in single oxidation states, such as zinc(II), function as structural elements in superoxide dismutase and zinc fingers, or, as an example from main group +2 ions, as triggers for protein activity—that is, calcium ions in calmodulin or troponin C... 

There are numerous compounds of lithium. Its atoms combine with many other elements to form a variety of compound molecules. Some form as single oxidation states, with one lithium cation combining with one anion (+1 combines with —1), and the more complex compounds involve two positive lithium cations combining with two negative anions (+2 combines with -2). Some examples follow ... 

Cadmium has a single oxidation state of +2. Several examples follow ... 

Xenon is noncombustible, and even though it is considered inert, it will combine with a few elements (i.e., oxygen, fluorine, and platinum). Xenon is the only member of group 18 that exhibits all of the even valence states of +2, +4, +6, and +8. It has similar oxidation states even though most periodic tables list a single oxidation state of zero. 

Similar to other rare-earths, thulium has a single oxidation state of +3. A general formula for the positive ion of thulium and the elements found in group 7 (fluorides) with a negative ion is expressed as follows ... 

In some cases, a single oxidation state of a given nonmetallic element may form more than one oxygen acid or derivatives of more than one oxy-acid, Pentapositive phosphorus has been shown, for example, to yield... 

It should be pointed out that even if one starts with a single oxidation state of iron in the presence of hydrogen peroxide, both states are soon produced. The ferric ion can oxidize perhydroxyl radical (H02) and/or its conjugate ion (02 ), as well as hydrogen peroxide. The chemistry of iron(III) with hydrogen peroxide has been comprehensively reviewed by Brown, Jones and Suggett.28... 

Americium. The low solubilities and high sorption affinity of thorium and americium severely limit their mobility under environmental conditions. However, because each exists in a single oxidation state—Th(IV) and Am(III)— under environmentally relevant conditions, they are relatively easy to study. In addition, their chemical behaviors provide valuable information about the thermodynamic properties of trivalent and tetravalent species of uranium, neptunium, and plutonium. 

Under many experimental conditions, it is difficult to maintain plutonium and some other actinides in a single oxidation state (Choppin, 1999 Neck and Kim, 2001). Depending on pH and solution composition, as many as four... 

The analyte in an oxidation/reduction titration must be in a single oxidation state at the outset. Often, however, the steps that precede the titration, such as dissolving the sample and separating interferences, convert the analyte to a mixture of oxidation states. For example, when a sample containing iron is dissolved, the resulting solution usually contains a mixture of iron(II) and iron(III) ions. If we choose to use a standard oxidant to determine iron, we must first treat the sample solution with an auxiliary reducing agent to convert all of the iron to iron(II). If we plan to... 

TABLE I Summary of Single Oxidation State Aqua Ions of Molybdenum... 

Coordination polymers of Zn(II) derived from bisthiopicolinamides show the best thermal stabilities and can be heated at 300°C for 6 h without changed The Zn(II) derivatives of bissalicaldimines also show the best thermal stability. The often found superior thermal stability of Zn(II) derivatives arise from its single oxidation state. Transition metals can be oxidized to higher states, catalyzing the decomposition of the polymer chains. 

Aluminum and Magnesium The electrochemical reactions in FFC of aluminum and magnesium are slightly different from those for iron since the former two elements have only a single oxidation state. Moreover, in the case of aluminum or... 

The transition metals often have a variety of oxidation states and usually have an oxidation state that s less than that of their group number. The oxidation state of the main group elements, however, is usually the same as the group number. For example, the main group elements Na, Mg, and AF all have a single oxidation state that s the same as their respective group numbers. 

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