Cuprous compounds

For reaction with hydrogen haUdes, the substitution reaction with haUde ion easily occurs when a cuprous or cupric compound is used as the catalyst (23) and yields a halogenated aHyl compound. With a cuprous compound as the catalyst at 18 °C, the reaction is completed in 6 h. Zinc chloride is also a good catalyst (24), but a by-product, diaHyl ether, is formed. 

Cupro-. cuprous, copper(I), cupro-. -chlorid, n. cuprous chloride, copper(I) chloride, -cy-aniir, n. cuprous cyanide, copper(I) cyanide cuprocyanide, cyanocuprate(I). -jodid, n. cuprous iodide, copper(I) iodide, -mangan, n. cupromanganese. -oxyd, n. cuprous oxide, copper(I) oxide, -salz, n. cuprous salt, cop-per(I) salt, -suifocyantir, n. cuprous thiocyanate, copper (I) thiocyanate, -verbin-dUDg, /. cuprous compound, copper(I) compound. 

Kupferozydul, n. cuprous oxide, copper(I) oxide, -hydrat, n. cuprous hydroxide, cop-per(I) hydroxide, -salz, n. cuprous salt, copper (I) salt, -verblndung,/. cuprous compound, copper(I) compound. 

As feed systems usually contain copper alloys, the use of amines for their protection may seem somewhat strange as copper is prone to attack in ammonia/carbon dioxide/oxygen environments, with the formation of complex cupric or cuprous compounds. The requisite degree of protection can be achieved, however, by maintaining the concentrations strictly within the acceptable target range. 

As previously mentioned, copper has two oxidation states. Compounds formed by +1 copper are known as cuprous compounds, and those with a +2 oxidation state are cupric compounds. Both oxidation states may be found in related compounds. 

A solution of the potassium salt is prepared in 50ml of water (using the directions given for the cuprous compound) and mixed with 8,5g of silver nitrate in 150ml of water. The bright yellow precipitate is isolated as in the previous procedure. Yield, quantitative. 

Cuprous Compounds. Same as Copper (I) Compounds. See in this Volume, p C 515-R... 

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. 

Valency and Ions.—Copper is usually considered to exhibit univalency in the cuprous compounds and bivalency in the cupric compounds. Its univalency in the cuprous compounds accords with the position of the metal in the periodic system, and is exemplified by the resemblance of the cuprous halides to the halides of silver and univalent gold, and also by the isomorphism of cuprous sulphide and silver sulphide. The bivalency of the atom in the cupric compounds is in agreement with the properties of many of its derivatives, a typical example being the isomorphism of cupric sulphate with the sulphates of ferrous iron, zinc, magnesium, and manganese. 

Besides these two main classes of copper compounds, there appear to be other types of copper derivatives, among them oxides of the formulae Cu40, CusO, Cu203, and Cu02. The cuprous ion, Cu, corresponds with the cuprous compounds, which are colourless in aqueous solution. The cupric ion, Cu, corresponds with the cupric compounds, which have a blue, green, violet, yellow, or brown colour in solution. 

Both cupric and cuprous salts act as oxidizers, the cupric derivatives being reduced to the cuprous or metallic condition, and the cuprous compounds to metallic copper. Alkaline solutions of cupric salts are employed in oxidation-processes in organic chemistry.2... 

Cuprous chloride, CuCl.—The pure chloride is more readily prepared than any other cuprous compound. A summary of the more important methods is appended. 

The conflict of evidence as to the molecular formula of cuprous chloride precludes dogmatic generalization regarding the valency of copper in the cuprous compounds. As a matter of expediency, it seems desirable to assume the univalency of the metal in these derivatives, a view supported by other arguments previously cited (p. 255). To explain the formation of double molecules, an interesting assumption... 

Very few cuprous salts oi oxygen acids exist. The stable cuprous compounds are either insoluble crystals containing covalent bonds or co- alent complexes. 

Other stable cuprous compounds are the insoluble substances cuprous oxide, Cu.,0 (red), cuprous sulfide, Cu. S (black), cuprous cyanide, CuCN (white), and cuprous thiocyanate, CuSCN (white). 

Ores of copper native copper, cuprite, chalcocite, chalcopyrite, malachite, azurite. Metallurgy of ores containing native copper, oxide and carbonate ores, sulfide ores. Gangue, flux, flotation, roasting of ores, matte, blister copper. Cupric compounds copper sulfate (blue vitriol, bluestone), Bordeaux mixture, cupric chloride, cupric bromide, cupric hydroxide. Test for cupric ion with Fehling s solution. Cuprous compounds cuprous chloride, cuprous bromide, cuprous iodide, cuprous oxide. Covalent-bond structure of cuprous compounds. 

Under what conditions can cuprous compounds or solutions be prepared ... 

Mercury forms two series of compounds, mercurous and mercuric, but the former are not compounds of monovalent Hg in the sense that cuprous compounds, for example, are derivatives of monovalent Cu. A number of elements form compounds in which there are metal-metal bonds but mercury is unique in forming, in addition to Hg and the normal mercuric compounds, a series of compounds based on the grouping (-Hg-Hg-). (Evidence for the formation of the Cdf ion in molten Cd2(AlCl4)2 at 250°C is limited to the observation of one Raman line. )... 

Cuprous compounds form stable complexes with acetonitrile. Kochi1 prepared colorless stable complexes of cuprous acetate in acetonitrile-acetic acid solution either by heating cupric acetate with copper powder in these solvents or by the reaction of cuprous oxide with acetic acid in acetonitrile ... 

The cuprous ion Cu+ is present in cuprous sulphate Cu2S04 but other cuprous compounds appear to be covalent, though the Cu+ ion is stabilised by complex ion formation. 

Cuprous compounds are diamagnetic and, except where color results from the anion or charge-transfer bands, colorless. 

In aqueous solution only low equilibrium concentrations of Cu+ (< 10 2M) can exist (see below) and the only cuprous compounds that are stable to water are the highly insoluble ones such as CuCl or CuCN. This instability towards water is due partly to the greater lattice and solvation energies and higher formation constants for complexes of the cupric ion, so that ionic Cu1 derivatives are unstable. 

The dipositive state is the most important one for copper. Most cuprous compounds are fairly readily oxidized to cupric compounds, but further oxidation to Cu111 is difficult. There is a well-defined aqueous chemistry of Cu2+, and a large number of salts of various anions, many of which are water-soluble, exist in addition to a wealth of complexes. 

Among the cuprous compounds which have been studied by X-ray methods, linear coordination is quite rare but it does occur in cuprite, Cu20 (100), which is isostructural with argentous oxide, and in cuprous chromite (33) and ferrite (127). In these three linearly coordinated oxide structures,... 

Solvents are used to carry dissolved or suspended resin and evaporate from the coating after application. Additives in small amounts are used as mildew inhibitors (cuprous compounds), surface-drying additives (manganese and cobalt naphthanates), and barrier-forming additives to protect the resin from heat and UV degradation. Fillers (talc and mica) decrease the permeability of oxygen and water in the coating. 

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