Nickel and Manganese

In view of their major application in aqueous battery systems more work has been carried out on the structural aspects of the oxides of these two metals than any of the systems discussed earlier. etails of the structure and reactivity of the nickel oxide battery materials can be found in recent reviews by Briggs and Oliva et al Both hydrous and anhydrous phases exist for both the Ni(II) hydroxide and Ni(III) oxyhydroxide systems. Most interesting are the comments of Le Bihan and Figlarz, and McEwen, with regard to turbostatic structures the latter are found in materials where the ordering of the oxide is quite limited, i.e., the systems consist of highly ordered nuclei linked in a disordered manner—the latter feature should certainly enhance mass transfer processes and may well be involved in many other hydrous oxide systems. 

According to Burke and Twomey nickel metal in base oxidizes just above 0 V (RHE) to form an initially anionic Ni(II) species. The Ni(II)/Ni(III) reaction, which is the main process of interest in battery systems, occurs at ca. 1.4 V (RHE). Thick oxide films 

The observed scheme is clearly speculative— its main function is to account for the observed electrochemical data. The greater poten- 

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LiNijXCoi-2jMrijD2, with y = 1/4 and 3/8, also suggested 2+ and 4+ as the predominant oxidation states for nickel and manganese, respectively, which then designates the nickel as the key electrochemi-cally active species. 

Mohr s Salt, (NH iSOi-FeSOi-QHzO.—Similar salts are formed with potassium, rubidium, and cesium, replacing ammonium, magnesium, zinc, cobalt, nickel, and manganese, replacing iron. 

The pentaphenylborole dianion was incorporated as a ligand in transition metal complexes with platinum and cobalt as well as with iron, nickel and manganese. An interesting formation of such a complex from 1-phenyl-4,5-dihydroborepin (53) was performed in boiling mesity-lene in the presence of iron pentacarbonyl. Six-membered borinate complexes were also found in the reaction mixture (77AG43). 

The fluorescence properties of two fulvic acids, one derived from the soil and the other from river water, were studied. The maximum emission intensity occurred at 445-450 nm upon excitation at 350 nm, and the intensity varied with pH, reaching a maximum at pH 5.0 and decreasing rapidly as the pH dropped below 4. Neither oxygen nor electrolyte concentration affected the fluorescence of the fulvic acid derived from the soil. Complexes of fulvic acid with copper, lead, cobalt, nickel and manganese were examined and it was found that bound copper II ions quench fulvic acid fluorescence. Ion-selective electrode potentiometry was used to demonstrate the close relationship between fluorescence quenching and fulvic acid complexation of cupric ions. It is suggested that fluorescence and ion-selective electrode analysis may not be measuring the same complexation phenomenon in the cases of nickel and cobalt complexes with fulvic acid. 

After filtration, addition of sodium sulphide to the clear solution effects the precipitation of the three metals, cobalt, nickel, and manganese, as sulphides. Digestion with the calculated quantity of ferric chloride oxidises the manganese sulphide to sulphate, which passes into solution. The residue consists of cobalt and nickel sulphides, which are washed and converted into their soluble sulphates by roasting. The sulphates are extracted with water, and converted into chlorides by addition of calcium chloride solution. Their separation is effected g.s follows The requisite fraction of the chloride solution is precipitated with milk of lime, and the insoluble hydroxides of nickel and cobalt thus obtained are oxidised to the black hydroxides by treatment with chlorine. The. washed precipitate is then introduced into the remainder of the chloride solution, and the whole is well stirred and heated, when the black hydrated oxide of nickel passes, into solution, displacing tlm Remainder of. the cobalt from the solution, into. the precipitate.. The final product is thus a suspension of hydrated peroxide.of cobalt,in p. solution of nickel chloride, from which idle cobalt precipitate is removed by filtration, washed, and ignited, to the black oxide. 

The contents of sodium, nickel and manganese in the samples were determined by Seiko Instruments SPS7000A induced couple plasma (ICP) spectrometer after dissolved in a mixed solution of HCl and H2O2. 

In recent years. X-ray crystallography has led to the discovery of several novel metalloclusters of complex architecture that contain at least four metal ions (4, 5). They represent the active site of several redox enzymes that contain molybdenum, nickel, and manganese, as well as the most commonly encountered iron and copper (Fig. 6). These enzymes are extremely specialized in the oxidation or reduction reactions of the smallest molecules and anions (which include N2, CO, and H2). A common feature of such clusters is that they are present in enzymes as part of a more extensive electron transfer chain that involves a series of... 

Figure 5 Downstream evolution of vanadium, nickel, and manganese concentrations measured in the dissolved load of the Amazon river showing different possible behaviors of trace elements in river systems. Major solutes and TDS follow the similar pattern to that of vanadium and correspond to a dilution of Andean waters by waters from the Amazonian lowlands (source Seyler and Boaventura, 2002).

Floret, G., Massa, V. Determination of cobalt, copper, nickel and manganese after chromatographic separation of their complexes with l-(2-pyridylazo)-2-naphthol. Ttav. Soc. Pharm. Montpellier 28, 129 (1969) C. A. 70, 31 731p (1969)... 

In the diet and at the tissue level, ascorbic acid can interact with mineral nutrients. In the intestine, ascorbic acid enhances the absorption of dietary iron and selenium reduces the absorption of copper, nickel, and manganese but apparently has little effect on zinc or cobalt. Ascorbic acid fails to affect the intestinal absorption of two toxic minerals studied, cadmium and mercury. At the tissue level, iron overload enhances the oxidative catabolism of ascorbic acid. Thus, the level of dietary vitamin C can have important nutritional consequences through a wide range of inhibitory and enhancing interactions with mineral nutrients. 

Incorporation of the catalyst into the monolith during manufacture. This method always leads to poor utilization of the catalytic material some is buried within the crystalline matrix and is not accessible to reactants. As the catalytic material modifies the monolith s physical properties, either a limit has to be placed on the amount of catalytic material incorporated or some deterioration in monolith performance has to be accepted. This method of manufacture is reserved for the preparation of base-metal catalysts, particularly nickel and manganese catalysts. Care has to be taken to avoid the formation of spinels, etc., although in some cases the formation of a complex oxide structure is actively sought. 

Finally, it should be pointed out that until now the application of ion chromatography to the analysis of heavy and transition metals such as iron, copper, nickel, and manganese in the ppb range in 50% sodium hydroxide solution [96, 97] was not possible. A concentration procedure developed by Kingston et al. [98] is used for the AAS analysis of heavy metals in sea water. It is based on the selective concentration of heavy metals on a macroporous iminodiacetic acid resin, where divalent cations are retained by chelation. Their affinity toward the stationary phase decreases in the order... 

Several years ago transition metal mediated reactions in the area of C-glycoside synthesis were primarily limited to palladium and to a lesser extent nickel and manganese. Over the last few years several other metals, including chromium, molybdenum, tungsten, cobalt, and rhodium, have been utilized in C-glycoside synthesis. This section discusses the chemistry of palladium, which is divided into Stille-type couplings and 7T-allyl complexes. This is followed by considerations of the chemistry of chromium and the above-listed metals. A review by Frappa and Sinou entitled Transition Metal Catalysed Fimctionalization at the Anomeric Center of Carbohydrates appeared in early 1997 [55]. 

Ceric fluoride, CeF4 H2O, is probably the only ceric halogen compound known in the solid form. It is a brown powder insoluble in water, prepared by adding hydrogen fluoride to ceric hydroxide. It readily forms double fluorides with the alkali metals and copper, cadmium, cobalt, nickel, and manganese. 

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