Metal structure, copper

I. B.Joralemon, Copper. The Encompassing Sto of Mankind s First Metal, H.owe]l-Notth Books, Berkeley, Calif., 1973. R. F. Mikesell, The World Copper Industry Structure and Economic Mnaljsis,]o m.s Hopkins Press, Baltimore, Md., 1979. 

Reductive coupling reaction of fluonnated vinyl iodides or bromides has been used as a route to fluorinated dienes [246, 247, 248, 249, 250. Generally, the vinyl iodide is heated with copper metal in DMSO or DMF no 1 ntermediate perfluorovmy I-copper reagent is detected. Typical examples are shown m equations 163-165 [246, 247, 249. The X-ray crystal structure of perfluorotetracyclobutacyclooctatetraene, prepared via coupling of tetrafluoro-l,2-diiodocyclobutene with copper, is planar... 

It represents the case of the reaction at the metal electrode in which ions of the same metal discharge at the electrode from the electrolyte. It can be said that copper ions in the electrolyte (copper sulfate solution) possess a free energy GCu(ej, and those in the copper metal electrode possess a free energy Ci(ll(-ril.. Then, if a copper ion is to leave its place in the copper sulfate electrolyte structure and occupy a position in the structure of the copper electrode, the free energy change accompanying this process will be ... 

Copper metal This solid at room temperature has a set volume and holds its shape. Its atoms are close together in an ordered crystalline structure and are vibrating in place. 

To illustrate this, take the situation in a very common and relatively simple metal structure, that of copper. A crystal of copper adopts the face-centered cubic (fee) structure (Fig. 2.8). In all crystals with this structure slip takes place on one of the equivalent 111 planes, in one of the compatible <110> directions. The shortest vector describing this runs from an atom at the comer of the unit cell to one at a face center (Fig. 3.10). A dislocation having Burgers vector equal to this displacement, i <110>, is thus a unit dislocation in the structure. 

Metal alloys can be amorphous, too. LiquidmetaF alloy is an amorphous alloy of zirconium mixed with nickel, titanium, copper, and beryllium. It is used in the heads of some brands of golf clubs. Traditional metal club heads may have microscopic gaps where planes of metallic crystals meet. These tiny gaps are a potential source of weakness. The amorphous alloy is non-crystalline, so the metal structure does not have potential breakage sites. 

Copper ions have been reduced in colloidal assemblies differing in their structures (55,56). In all cases, copper metal particles are obtained. Figure 9.3.1 shows the freeze-fracture electron microscopy (FFEM) for the various parts of the phase diagram. Their structures have been determined by SAXS, conductivity, FFEM, and by predictions of microstructures that require only notions of local curvature and local and global packing constraints. 

Fig. 47. SEM of tubules and helices formed from 21 (m = 8, n = 9) at 50% 2-propanol in water that were subsequently coated with copper metal as described in the text Note that all helical structures are right-handed and that the pitch of the helices is somewhat variable. Scale bar = 2.48 pm [361]...

Metals such as iron, aluminum, and copper can have weak oxide or oxide/metal structures. In such a case, a coupling agent would be of little value until the weakness in the oxide layer had been remedied failure will occur in the weakest region. 

Because copper is a very good conductor of electricity, it is used for electrical wiring and cables (Figure 5.16). Pure copper is also used in the manufacture of cooking utensils owing to its high thermal conductivity, a property of its metallic structure (Chapter 3, p. 55). 

The structure of the methylxanthate analogue, (Ph3P)2Cu(S2COMe), is also known and this essentially adopts the same structure as described above (127). The remaining copper xanthate structures are mixed-metal species. 

It is noteworthy that components other than alumina often have detrimental chemical and physical effects on the catalyst. For example, Herman et al. (77) reported that addition of ceria to the Cu/ZnO catalyst lowered methanol conversion by a factor of 5, despite the presence of a large concentration of microparticulate copper metal. This effect was explained by the ability of ceria to drive copper from the active state in zinc oxide solution to inactive metallic copper. Chromia, which had been used as a component of catalysts for methanol for a considerable period of time, is a suitable structural promoter, but some preparations result in an increase of concentration of side products such as higher alcohols (39), dimethyl ether (47), or even hydrocarbons. 

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