Indium metal

Analysis. Indium can be detected to 0.01 ppm by spectroscopic analysis, using its characteristic lines in the indigo blue region, at wavelengths 4511.36, 4101.76, 3256.09, and 3093.36 nm. Procedures for the quantitative deterrnination of indium in ores, compounds, alloys, and for the analysis of impurities in indium metal are covered thoroughly in the Hterature (6). 

AppHcations for electroplated indium coatings include indium bump bonding for shicon semiconductor die attachment to packaging substrates and miscehaneous appHcations where the physical or chemical properties of indium metal are desired as a plated deposit. 

The usual valence of indium is three, although monovalent and bivalent compounds of indium with oxygen, halogens, and Group 15 (VA) and 16 (VIA) elements ate well known. The lower valence compounds tend to disproportionate into the trivalent compound and indium metal the trivalent compounds ate stable. 

Sulfates. Indium metal and its oxides dissolve in warm sulfuric acid to give a solution of the trisulfate [13464-82-9], In2(S0 2- It is a white, crystalline, deUquescent soHd, readily soluble in water that forms double salts with alkaLi sulfates and some organic substituted ammonium bases. Concentration of the acidified trisulfate solution produces indium acid sulfate crystal [57344-73-7], In(HS0 2> other reaction conditions give basic sulfates. 

As shovm in Eq 6 59, Rapoport has prepared sinefungin, nucleoside andbiodcs, via nitro-aldol reaction, dehydradon, and reducdon v/iihZn in acetic acid fi-Niiro styrenes are selecdvity reduced to the corresponding oximes by indium metal in aqueous methanol under neutral conthdons ... 

The chemistry of indium metal is the subject of current investigation, especially since the reactions induced by it can be performed in aqueous solution.15 The selective reductions of ethyl 4-nitrobenzoate (entry 1), 2-nitrobenzyl alcohol (entry 2), l-bromo-4-nitrobenzene (entry 3), 4-nitrocinnamyl alcohol (entry 4), 4-nitrobenzonitrile (entry 5), 4-nitrobenzamide (entry 6), 4-nitroanisole (entry 7), and 2-nitrofluorenone (entry 8) with indium metal in the presence of ammonium chloride using aqueous ethanol were performed and the corresponding amines were produced in good yield. These results indicate a useful selectivity in the reduction procedure. For example, ester, nitrile, bromo, amide, benzylic ketone, benzylic alcohol, aromatic ether, and unsaturated bonds remained unaffected during this transformation. Many of the previous methods produce a mixture of compounds. Other metals like zinc, tin, and iron usually require acid-catalysts for the activation process, with resultant problems of waste disposal. 

Although not formally the enamine synthesis, reaction of an enamine with methyl hromoacetate in the presence of indium metal leads to a-aUcylation R2N-CH=CHR R2N-CH(R )CHR. ... 

Indium metal reduces the pyridine ring in quinoline in aqueou sethanol solution.Samarium iodide (Sml2) reduces pyridine in aqueous THF ° and phenol in MeOH/KOH. ... 

The reaction can also be carried out using indium metal. Under these conditions InCl3 is presumably generated in situ.135... 

One notable result is the treatment of 2-hydroxy cyclic ether analog, 2-deoxy-D-ribose with aniline in water catalyzed by InCl3 to afford the novel tricyclic tetrahydroquinoline compounds (Eq. 12.60). The reaction can also be catalyzed by recoverable cation-exchange resin instead of indium chloride.132 By using a stoichiometric amount of indium metal, a domino reaction of nitroarenes with 2,3-dihydrofuran generates the same products. 133... 

Indium is silvery-white and malleable and looks much like aluminum and tin. However, it is softer than lead. Indium metal is so soft that it cannot be wiped onto other surfaces as with a graphite pencil. Because it is noncorrosive and does not oxidi2e at room temperatures, it can be polished and will hold its shine better than silver. Its melting point is 156.60°C, its boiling point is 2,075°C, and its density is 7.31 g/cm. ... 

Indium metal dust, particles, and vapors are toxic if ingested or inhaled, as are most of the compounds of indium. This requires the semiconductor and electronics industries that use indium compounds to provide protection for their workers. 

In this context, Yadav and coworkers have recently developed a mild and efficient procednre for the selective rednction of / -nitrostyrenes 22 to oximes 23 using indium metal in aqueous methanol under neutral reaction conditions (Scheme 19). Similarly, a-alkoxy oximes 24 are formed in good yields by the treatment of nitroolefins with metalhc indium and trimethylsilyl chloride in anhydrous methanol (Scheme 19). 

The reduction of /3-nitrostyrenes with indium metal in aqueous ammonium chloride gave a mixture of E and Z isomers while the reduction of -methyl-/ -nitrostyrenes with indium powder in the presence of trimethylsilyl chloride gave exclusively the E isomer. 

When heated with excess hydrogen at 450°C to 500°C, indium trioxide is reduced to indium metal ... 

The syntheses described below allow such a cycle of operations to be circumvented. As reported previously,2 the electrochemical oxidation of indium metal at room temperature in an organic solvent system yields neutral, anionic, or cationic complexes of indium(III) within 2-3 hours, usually in good crystalline form. These syntheses are significantly quicker and more convenient than the procedures used in this laboratory in previous work. 

Indium metal (0.5 g) is maintained at +50 V in a solution phase of 100 mL of benzene-methanol (3 1, v/v) containing 10 mg of tetraethylammonium perchlorate. Benzene is dried with sodium-naphthaquinone and is distilled before use (all under nitrogen) methanol is analytical grade reagent. The cell must be cooled in an ice bath throughout the experiment, since appreciable amounts of heat are evolved. 

Indium metal (0.85 g) is maintained at +15 V in a solution phase of 100 mLof 50 50 benzene-dimethyl sulfoxide (dmso). Benzene is purified as in Section A above dimethyl sulfoxide is dried over 4A molecular sieves before use. The cell is cooled in an ice bath throughout the experiment. Chlorine gas is bubbled slowly through the solution phase (about one bubble per second from a 2-mm tube) for 2 hours. At the end of this period, the solution is brown, and most of the indium has dissolved approximately 0.1 g of corroded material remains. 

Indium metal (0.8 g) is maintained at +50 V in a solution phase of 80 mL of 2,4-pentanedione and 5 mL of methanol containing 50 mg tetraethylammonium perchlorate. Under these conditions, a current of 100 mA is recorded. Electrolysis is continued for 2 hours at room temperature the metal is almost completely consumed in this period. The final solution is pale yellow, suggesting some decomposition of the diketone. 

FIGURE 2.30 (a) DSC trace for the melting of indium metal (b) integration of the power data to give... 

Irradiation. Indium metal was melted into a stainless steel tube,... 

Chemistry. The indium metal was melted (mp 156°C) into a flask where it was dissolved in hot 6 M HC1. Since the target material was known to contain Sb impurity, filtration was required at this point in the procedure. After filtration the solution was adjusted to 3 M HC1 by the addition of a suitable volume of distilled water. Table I is a list of the elements that must be separated to obtain pure Cd-109. This solution was applied to an AG-1X8 anion column, 200 to 400 mesh (8). The column was 1.2 cm in diameter with a total bed volume dependent on the quantity of target used. Bed volumes of 20 ml and 40 ml were successfully used. 

A solution of [Mo302S2(H20)9]4+ in 4M Hpts (pts = para-toluene sulfonate) was reacted with indium metal for 24 hr at room temperature and stored in a refrigerator for a few days to form [Mo4(p3-S)2(p2-0)4 (H2O)10](pts)4 10H2O (101). The cluster core of Mo4S204 is similar to those of Mo4S6 cluster complexes. 

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