Oxygen with nickel

Ni(Ph3As0)4Br]Br.H20.1.5(toluene), square-pyramidal geometry about nickel with oxygen atoms in basal positions (As—01.66-1.68 A), Ni—02.00A ... 

Copper and brasses in the systems are more resistant to corrosion because of a stable oxide film however, if ammonia is present together with oxygen, corrosion of copper and copper oxide rapidly occurs. The corrosion is an oxidation process and results in the formation of the ammonia-copper complex [Cu(NH3)42+], Corrosion of nickel and zinc components also may occur in like fashion. 

This type of catalyst is not limited to nickel other examples are Raney-cobalt, Raney-copper and Raney-ruthenium. When dry, these catalysts are pyrophoric upon contact with air. Usually they are stored under water, which enables their use without risk. The pyrophoric character is due to the fact that the metal is highly dispersed, so in contact with oxygen fast oxidation takes place. Moreover, the metal contains hydrogen atoms and this adds to the pyrophoric nature. Besides the combustion of the metal also ignition of organic vapours present in the atmosphere can occur. Before start of the reaction it is a standard procedure to replace the water by organic solvents but care should be taken to exclude oxygen. Often alcohol is used. The water is decanted and the wet catalyst is washed repeatedly with alcohol. After several washes with absolute alcohol the last traces of water are removed. 

Figure 2.1 Real-time photoemission study (hv = 6.2 eV) of the interaction of oxygen (Po2 = 10- Torr) with a nickel surface at 300 K. The photocurrent decreases initially (A B), then recovers (B-C), before finally decreasing (CD). Surface reconstruction occurs (B-C) with further support from studies of the work function. The work function measured by the capacitor method15 increases by 1.5 eV with oxygen exposure at 80 K followed by a rapid decrease on warming to 295 K and an increase on further oxygen exposure at 295 K. These observations suggest that three different oxygen states are involved in the formation of the chemisorbed overlayer. (Reproduced from Refs. 15, 42).

In order to avoid contamination of the alloys with oxygen, Gharpurey and Emmett (113) decided to attempt to prepare Cu-Ni catalysts by a film technique. They prepared thin films of copper on nickel or nickel on copper by successive evaporation and heated them overnight at 300°C in... 

Thermochemical Cycles Testing the Formation of Gaseous (Cycle 1) or Adsorbed (Cycle 2) Carbon Dioxide by the Interaction of Carbon Monoxide with Oxygen Preadsorbed on Gallium-Doped Nickel Oxide ... 

Catalytic destruction. Catalytic conversion of hypochlorite to chloride and oxygen can be facilitated by nickel. With the Hydecat process, ICI has a commercial solution available. 

In this reaction the metal behaves as a Lewis acid and accepts a pair of electrons from the Lewis base (ligand). In this case the ligand is water, with the oxygen atom donating one of its lone pairs to the nickel. The oxygen atom is called the donor atom. In this complex, there are six donor atoms. 

Fig. 11. Comparison of N(ls) spectra observed after NO adsorption 1, clean nickel exposed to NO at 290 K 2, nickel preoxidized at 290 K, NO adsorbed at 80 K 3, nickel with chemisorbed oxygen layer present (formed at 80 K), NO also adsorbed at 80 K 4, clean nickel exposed to NO at 80 K.

Nickel films completely covered with oxygen will not adsorb hydrogen when exposed to this gas immediately after oxidation, but will regain their ability to adsorb hydrogen after several hours. Hydrogen thus adsorbed is not able to hydrogenate ethylene. Heats of adsorption measurements of this type of hydrogen adsorption have not been made. 

Nickel tetracarbonyl is both a fire and explosion hazard and is a highly toxic compound. It is a volatile flammable liquid with a flash point (closed cup) -4°F (-18°C) and forms explosive mixtures with air. It explodes when heated in oxygen or air or when it is dry and shaken vigorously with oxygen in the presence of mercury or mercuric oxide. 

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