Binary copper compounds

Despite the tremendous amount of work on the binary compounds, copper chalcogenide halides were first reported in 1969 (304). Nine compounds of selenium and tellurium have been found, and they are listed in Table 1. Copper sulfide halides are still unknown. 

For example, the results in Table 3 suggest that binary carbonyls of copper, silver and gold which have been detected spectrometrically in matrices at very low temperatures27, contain metal-CO bonds which are approximately of the same strength as those in Mn2(CO)i0. Similar considerations apply to carbonyls of palladium and platinum which have also been detected by matrix isolation spectrometry28. All of these binary compounds are unstable with respect to [M(c) + CO(g)J at room temperature. 

A large number of binary AB compounds formed by elements of groups IIIA and VA or IIA and VIA (the so-called III-V and II-VI compounds) also fcrystallize in diamond-like structures. Among the I-VII compounds, copper (I) halides and Agl crystallize in this structure. Unlike in diamond, the bonds in such binary compounds are not entirely covalent because of the difference in electronegativity between the constituent atoms. This can be understood in terms of the fractional ionic character or ionicity of bonds in these crystals. 

There is a lot of oxygen in the atmosphere, and over the millions of years since the Earth was formed many metals have combined with oxygen to form compounds called oxides. Iron, for example, occurs in the molten core of our Earth, and is often found in the Earth s crust as the ore haematite, which is iron oxide. Iron oxide is a binary compound, which means it contains only two elements. Notice that its name ends with ide . This is true for all binary compounds. Metals tend to combine with non-metals. Where a binary compound is made up of a metal and a non-metal, the first name of the compound is simply the name of the metal it contains and the second is the name of the non-metal, changed to end in ide for example, the compound between copper and chlorine is copper chloride. 

With the hope that there exist copper oxide compounds with higher Tc, we have undertaken an extensive matrix experiment, in which composition and processing conditions were varied for a wide variety of rare earth-alkaline earth-copper-oxide combinations. Most of the higher Tc, reports have involved Y-Ba-Cu-O compositions, and so this system received the major portion of our attention. We also examined other isoelectronic elements such as Sc, La, and Lu substituting for Y and, to a lesser extent, Sr for Ba. Binary rare earth-... 

Cuprous Binary Compounds. The oxide and sulfide are more stable than the corresponding Cu11 compounds at high temperatures. Cu20 is made as a yellow powder by controlled reduction of an alkaline solution of a cupric salt with hydrazine or, as red crystals, by thermal decomposition of CuO. A yellow hydroxide is precipitated from the metastable Cu+ solution mentioned above. Cu2S is a black crystalline solidprepared by heating copper and sulfur in absence of air. 

Binary Copper(ll) Compounds. Black crystalline CuO is obtained by pyrolysis of the nitrate or other oxo salts above 800° it decomposes to CuzO. The hydroxide is obtained as a blue bulky precipitate on addition of alkali —hydroxidenxrcuprkrsolutions warming an aqueous slurry dehydrates this to the oxide. The hydroxide is readily soluble in strong acids and also in concentrated alkali hydroxides, to give deep blue anions, probably of the type [Cu (OH)2 2]2+. In ammoniacal solutions the deep blue tetraammine complex is formed. 

The unit cell of a binary compound of copper and oxygen is shown here. Given this image and the ionic radii rc + = 0.74 A and ro>- = 1.26 A, (a) determine the empirical formula of this compound, (b) determine the coordination numbers of copper and oxygen, (c) estimate the length of the edge of the cubic unit cell, and (d) estimate the density of the compound. 

Yamakawa N, Jiang M, Grey CP (2009) Investigation of the conversion reaction mechanisms for binary copper(II) compounds by solid-state NMR spectroscopy and X-ray diffraction. Chem Mater 21(14) 3162-3176... 

Burdett JK, Graham MA, Turner JJ. Binary compounds of dinitrogen with nickel, chromium, platinum, and copper a vibrational investigation of the metal-dinitrogen linkage. J Chem Soc Dalton Trans. 1972 1620-1625. 

Copper Sulphide Nanoparticles Among the chalcogenide semiconductor nanoparticles, copper sulphides have been synthesized by a variety of methods as shown in Table 3. Various nanoparticles (plates, tubes, wires, spheres and other architectures) of these binary compounds have been prepared by several techniques and effect of process parameters have been extensively explored with a view to generate controlled size and shape of nanoparticles. 

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