Mixed metal oxides nickel compounds

The chemistry of oxo compounds of nickel(II) is very limited if the simple oxide NiO and the mixed-metal oxide Ba3Ni04 are excluded.1475-1477 Dioxygen complexes of nickel(H) are not cited in a recent review article.1478... 

Heavy metal oxides of compounds, such as copper oxide, nickel oxide, cobalt oxide, and magnesium dioxide, are mixed in the charge to catalyze the reaction of the potassium superoxide with carbon dioxide and moisture. It is important, however, that only a portion of the superoxide be mixed with catalyst to avoid excessive liberation of oxygen. 

The hydrolysis of [Ni(H20)6p has been studied by some authors. It has been found that polynuclear species are formed in alkaline solution, e main product being the tetranuclear cation [Ni4(OH)4] . " A few solid compounds which contain nickel(II) linked only to hydroxide ions were reported, namely M2[Ni(OH)6] (M = Ba, Sr) and Na2[Ni(OH)4]. " The chemistry of oxo compounds of nickel(n) is very limited if the simple oxide NiO and the mixed-metal oxide BaaNiOa are excluded. Dioxygen complexes of nickel(II) are not cited in a recent review article. ... 

There have been a number of studies of the physical and bonding behavior of these mixed transition-metal oxides, which conclude that in the fully lithiated compounds the cobalt is trivalent, the nickel predominantly divalent, and the manganese tetra-valent. Thus, the electrochemically active species is predominantly nickel with the cobalt playing an... 

Most of the world s nickel comes from deposits in Ontario, Canada. These deposits are believed to have formed from a meteorite impact (most meteorites have high nickel content). The nickel occurs as a sulfide compound mixed with copper and iron sulfides. To produce nickel, the sulfides are roasted in air to form metal oxides, and then they are reduced to the elemental metals with carbon. The metal mixture is heated in the presence of carbon monoxide, forming nickel carbonyl, which has a boiling point of 43 °C and can be collected as a gas. 

Corrosion of condensate lines is a serious problem. It is compounded where both oxygen and carbon dioxide are present because it causes considerable quantities of hematite (Fe203) to develop. Corrosion of other boiler plant components, such as FW heaters, adds more metals to the mix, and corrosion debris typically includes iron, copper, nickel, zinc, and chromium oxides. 

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