Oxidation states range

Ground-state electronic configuration is ls 2s 2p 3s 3p 3i 4s. Manganese compounds are known to exist in oxidation states ranging from —3 to +7 (Table 2). Both the lower and higher oxidation states are stabilized by complex formation. In its lower valence, manganese resembles its first row neighbors chromium and especially iron ia the Periodic Table. Commercially the most important valances are Mn, Mn ", or Mn ". ... 

Chromium is able to use all of its >d and As electrons to form chemical bonds. It can also display formal oxidation states ranging from Cr(—II) to Cr(VI). The most common and thus most important oxidation states are Cr(II), Cr(III), and Cr(VI). Although most commercial applications have centered around Cr(VI) compounds, environmental concerns and regulations ia the early 1990s suggest that Cr(III) may become increasingly important, especially where the use of Cr(VI) demands reduction and incorporation as Cr(III) ia the product. 

Stable nucleophilic carbenes are capable of forming isolable complexes with a variety of main group species in oxidation states ranging from +1 to +6. The majority of the complexes that have been reported thus far possess 1 1 stoichiometry however, there are several instances of 2 1 complexation and one example of a 3 1 complex. Although, in principle, it is possible to write double-bonded (carbene)C = EX canonical forms to describe the interactions between carbenes and main group entities (EXJ, in the stable nucleophilic carbene complexes considered here the bonding is predominantly of the... 

Chromium in the crystalline form is a steel-gray, lustrous, hard metal characterized by an atomic weight of 51.996, an atomic number of 24, a density of 7.14 g/cm3, a melting point of 1857°C, and a boiling point of 2672 C. Four chromium isotopes occur naturally Cr-50 (4.3%), -52 (83.8%), -53 (9.6%), and -54 (2.4%), and seven are man-made. Elemental chromium is very stable but is not usually found pure in nature. Chromium can exist in oxidation states ranging from -2 to +6, but is most frequently found in the environment in the trivalent (+3) and hexavalent (+6) oxidation states. The +3 and +6 forms are the most important because the +2, +4, and +5 forms are unstable and are rapidly converted to +3, which in turn is oxidized to +6 (Towill et al. 1978 Langard and Norseth 1979 Ecological Analysts 1981 USPHS 1993). 

Addition of carbon monoxide to hydrocarbon solutions of M2(OR)6 (M=M) compounds leads to M(CO)6 and alkoxy derivatives of Mo and W in oxidation states ranging from + 4 to +6. The course of the reaction depends upon the metal and the alkoxy ligand. In the case of the reaction between Mo2(OBu )6 and CO, the stoichiometric reaction (71) has been established.262... 

Complexes of technetium in oxidation states ranging from (-1) to (VII) have been prepared chemically and characterized. However, historically only the higher oxidation states (IV), (V) and (VII) have been of major importance in radiopharmaceutical formulations. More recently there has been increased interest in lower oxidation state technetium complexes for medical applications, and the use of ir-acceptor ligands has allowed the preparation of Tc1 complexes which are stable in vivo. The coordination chemistry of technetium has been described in Chapter 42 and recent reviews have been provided by Davison21 and by Schwochau.22 Reviews which relate to medical applications of technetium are given by Jones and Davison,549 Deutsch et al.,20 Deutsch and Barnett,550 Siedel551 and Clarke and Fackler.552 The in vivo chemistry of "mTc chelates has been described by Eckelman and Volkert,553 while the structures of technetium complexes, determined by X-ray diffraction techniques, have been reviewed by Bandoli et ai554... 

Chromium is a metallic element with oxidation states ranging from chromium(-II) to chromium(+VI). 

Chromium is used extensively in metal plating and is found as a trace element in natural waters. Chromium is capable of assuming oxidation states ranging from 2+ to 6+ with Cr (III) the most stable. Chromium (III) is essential for good health in humans as it plays a role in glucose metabolism. Chromium (III) compounds show little or no toxicity, whereas other chromium compounds, particularly chromium (VI), can be toxic and carcinogenic. 

Vanadium is used as an additive to steel and cast iron. This element has been found to be essential for the development of chicks and rats, but its role in humans is more ambiguous [5]. Vanadium has oxidation states ranging from +5 to — 1, with +4 the most stable under normal conditions. The chemistry of vanadium is com-... 

Nitrogen occurs in numerous oxidation states ranging from —3 (as in ammonia) to +5 (as in nitrate). It... 

Sulfur, a reactive element with stable oxidation states ranging from —2 to +6, is among the 10 most abundant elements in the Earth s crust. In living organisms, sulfur occurs mainly as sulfhydryl groups in amino acids and their polymers. At an approx-... 

These form a large and interesting series of substances, in oxidation states ranging form +3 to +6, illustrating principles of structure and property. The structures of the uranium halides are shown in Figure 10.4. 

Copper complexes are known in oxidation states ranging from 0 to +4, although the +2 (cupric) and the +1 (cuprous) oxidation states are by far the most common, with the divalent state predominating. Only a relatively small number of Cu complexes have been characterized and the Cu° and oxidation states are extremely rare. A few mixed valence (see Mixed Valence Compounds) polynuclear species have also been isolated examples include a CuVCu species and a Cu /Cu catenane. The coordination numbers and geometries (see Coordination Numbers Geometries) of copper complexes vary with oxidation state. Thus, the majority of the characterized Cu complexes are square planar and diamagnetic, as is common for late transition metals with d electronic configurations. 

The coordination chemistry of Ni featmes a very wide variety of mono- and poly dentate ligands, with metal oxidation states ranging from 0 to -KV, although organometallic Ni and Ni species have been reported. The most common oxidation state by far is Ni although Ni° complexes are also well known. Ni and Ni species are less common, while Ni complexes are established only for certain ligand types. Table 1 summarizes typical data on the oxidation states and stereochemistries of Ni complexes. The basic electronic and spectral featmes of Ni complexes have been reviewed. ... 

All characterized Pd(I) compounds have Pd-Pd or Pd-M bonds. Accordingly, the paramagnetic behavior anticipated for a d configuration is not found in these multinuclear diamagnetic complexes as the expected unpaired electron is in fact involved in the formation of a metal-metal bond. There are some palladium clusters in formal oxidation states ranging from 0 to -1-1 (metal-metal bonds do not count in the assignment of oxidation states) that will be considered here. 

Nitrogen forms a series of oxides in which its oxidation state ranges from +1 to +5, as shown in Table 19.2. 

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