Copper univalent

The interatomic distances found are V—S = 2.186 0.040 A and Cu—S — 2.285 i 0.014 A. The Cu—S distance is somewhat smaller than the sum of the tetrahedral radii2) for sulfur and univalent copper, 2.39 A. As in the case of chalcopyrite, this probably indicates that the valence states are not well defined as CuIiVvSi, but fluctuate, the copper resonating between cuprous and cupric states and the vanadium between quinquivalent and lower states. 

Univalent halides—e.g. NH l.AgCl CsCl.CuCl 2KCl.CuCl etc. The halides of the alkali metals do not often unite together to form stable complexes. Univalent copper, silver, and gold form double chlorides with the alkali halides, while the corresponding double bromides of silver and gold and the double iodide of silver have not been made. The facts can be summarized in the form of a scheme due to P. Pfeiffer (1902), where the hyphens represent compounds which have not yet been prepared ... 

In coal, copper shows an organic affinity different from the Mellor and Maley (14) series, and zinc appears to be completely associated with the inorganic matter. Copper in the physicochemical environment of coal deposition can be reduced to the univalent state (5). Univalent copper cannot be expected to behave like the bivalent metals. The ionic potential of univalent copper fits reasonably well into the organic affinity series (Figure la). 

In contrast to the tertiary amines, trialkylphosphines have strong donor properties and form exceedingly stable coordination complexes with a wide variety of metal salts such as those of univalent copper and gold, and bivalent platinum, palladium, and mercury.1 Like phosphine itself, many of these tertiary alkylphosphines are highly flammable, toxic, and extremely susceptible to air oxidation. Ease of oxidation first decreases and then increases as the alkyl group becomes larger.2 3,4 5 The n-butyl compound is thus a convenient member of this group for preparation. 

Silicon and univalent copper chloride powders are mixed and pelleted. The pellets are dried and treated with hydrogen at 300 °C. Copper chloride is reduced, and silicon particles are covered with free copper ... 

There are several activation techniques. One of the most widespread techniques is the thermal treatment of the contact mass in hydrogen flow or hydrogen-nitrogen mixture at 1050 °C for several hours. According to the second technique, the mass is submerged into a 30% solution of bivalent copper chloride for 1 minute, which changes into univalent copper chloride ... 

Apart from antimony, there are other good promoters of the direct synthesis of methylchlorosilanes, which increase the yield of dimethyldichlorosilane, such as arsenic and zinc chloride. If it is necessary to increase the yield of alkylhydridechlorosilanes, one should use univalent copper chloride, cobalt, and titanium. The addition of tin or lead into contact mass increases the yield of dimethyldichlorosilane up to 70% the yield of ethyldi-chlorosilane is increased to 50-80% when contact mass receives 0.5-2% of calcium silicide (Ca2Si). In the synthesis of phenylchlorosilanes effective promoters are zinc, cadmium, mercury or their compounds. In particular, the introduction of zinc oxide (up to 4%) into contact mass may increase the diphenyldichlorosilane content up to 50%, and the introduction of a mixture of zinc oxide and cadmium chloride, even up to 80%. 

In water, the cuprous ion, Cu+, may not exist in appreciable quantities, for it disproportionates (dismutates) into the cupric ion, Cu2+, and copper metal. Certain very slightly dissociated complexes of univalent copper (for example, Cu(CN)J3 and CuClJ") are stable in aqueous solutions and relatively insoluble cuprous compounds (for example, CuCl, and CU2O) may survive in the presence of water if strong oxidizing agents are not also present. The iodide, Cul, and sulfide, Cu2S, are particularly stable. Aside from the instability of the hydrated Cu+ ion, the chemistry of univalent copper is quite similar to that of univalent silver. 

Zeolites containing 3d transition-metal ions were considered in Beran et al. (109-112). The peculiarities of the donor-acceptor interactions of these cations located within six-membered rings with a zeolite lattice were discussed in terms of atomic charges, bond orders, and orbital energies. The redox properties of the cations, the acid-base properties of zeolites, and the dependence of these characteristics on the Si/Al ratio were discussed as well. The authors noted that the forms containing univalent copper and nickel ions should possess the highest electron-donor ability and consequently the... 

The distinction between these planar bonds in divalent copper and the tetrahedral sp3 bonds in univalent copper will be noted. 

The copper ion produced by this dissociation is then reduced at the electrode to copper (I) in the presence of excess chloride ion (which stabilises the univalent copper),... 

This approach to the synthesis relies on the capability of an ion of univalent copper to form strong complexes both with two linear molecules the macrocycles of which can be produced by cyclization with one such molecule and a already formed cycle. In this case, Cu orients them spatially so that closing of linear molecules into a ring gives rise to a metal-catenane ... 

The complex cyanides of cadmium and univalent copper are slightly dissociated (omitting the intermediate stages) ... 

The study of the influence of the concentration of univalent copper on copper open-circuit potential. Elektrokhimiya, 9 (10), 1460-1467. 

The alkali metal salts generally melt without decomposition, and where there are no entries in Table 3.1 there appear to be no available data. On the other hand for the univalent copper, silver and thallium salts the empty spaces in this table denote that the salts decompose on heating or are unstable in the first place (in particular Cu (I) salts). In the case of the divalent metal salts, the oxides and sulfides melt at very high temperatures, but most of the salts with polyatomic anions decompose on heating. Univalent molten salts with monatomic anions boU at ambient pressures without decomposition, hence many of their boUing points could be reported in Table 3.1. This is rarely the case for molten salts with polyatomic anions, exceptions being some of the hydroxides and cyanides. 

Although many transition metals are capable of forming complexes with N, only univalent copper compounds comply with the above requirements. " - - The initial ligand N and copper salts S (CuX, X = Cl, Br, 1, OCOMe) do not absorb light with X > 300 nm, whereas their adducts [S—N] display an intense charge-transfer absorption band with X 370 nm. Irradiation of these complexes by light of A, = 313 nm results in the formation of Q as the sole product with reasonably high quantum yields (O = 0.2-0.4). 

---