Indium In

The use of indium in acpieous solution has been reported by Li and co-workers as a new tool in org nometallic chemistry. Recently Loh reported catalysis of the Mukaiyama-aldol reaction by indium trichloride in aqueous solution". Fie attributed the beneficial effect of water to a eg tion phenomena in connection with the high internal pressure of this solvenf This woric has been severely criticised by... 

Differential pulse polarography is used to determine the concentrations of lead, thallium, and indium in a mixture. ... 

The abundance of indium in the earth s cmst is probably about 0.1 ppm, similat to that of silver. It is found in trace amounts in many minerals, particulady in the sulfide ores of zinc and to a lesser extent in association with sulfides of copper, tin, and lead. Indium follows zinc through flotation concentration, and commercial recovery of the metal is achieved by treating residues, flue dusts, slags, and metallic intermediates in zinc smelting and associated lead (qv) and copper (qv) smelting (see Metallurgy, EXTRACTIVE Zinc and zinc alloys). 

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). 

The supplanting of germanium-based semiconductor devices by shicon devices has almost eliminated the use of indium in the related ahoy junction (see Semiconductors). Indium, however, is finding increased use in III—V compound semiconductors such as indium phosphide [22398-80-7] for laser diodes used in fiber optic communication systems (see Electronic materials Fiber optics Light generation). Other important indium-containing semiconductors include indium arsenide [1303-11-3] indium antimonide [1312-41 -0] and copper—indium—diselenide [12018-95-0]. 

Halides. Indium trichloride [10025-83-8] InCl, can be made by heating indium in excess chlorine or by chlorinating lower chlorides. It is a white crystalline soHd, deUquescent, soluble in water, and has a high vapor pressure. InCl forms chloroindates, double salts with chlorides of alkaLi metals, and organic bases. 

Indium dichlotide [13465-11 -7/, InCl, made by heating indium in hydrogen chloride or by reduction of InCl iu H2/HCI, forms colorless crystals. Indium monochloride [13465-10-6] InCl, can be formed by passing InCl vapor over heating indium. 

Organometallic Compounds. The predominant oxidation states of indium in organometalUcs are +1 and +3. Iridium forms mononuclear and polynuclear carbonyl complexes including [IrCl(P(C3H3)3)2(CO)2] [14871-41-1], [Ir2014(00)2] [12703-90-1], [Ir4(CO)22] [18827-81 -1], and the conducting, polymeric [IrCl(CO)3] [32594-40-4]. Isonitnle and carbene complexes are also known. 

Rapp (1961) has confirmed this equation in a study of the oxidation in air of Ag-In alloys at 550°C. The reaction proceeds with tire internal formation of In203 particles over a range of indium concenuations, but at a critical mole fraction of indium in the alloy, external oxidation occurs with the growdr of a layer of In203 covering the alloy. The n airsitioir from internal to external oxidation was found by Rapp to occur at the mole fraction of indium cone-sponding to... 

In overlay bearings operating above about 140°C, the tin or indium in the overlay diffuses towards, and alloys with, the underlying copper, depleting the overlay and reducing its resistance to corrosion. This depletion by diffusion can be combatted by the use of a diffusion barrier or dam , e.g. a nickel-rich layer between the bearing alloy and, the overlay . 

Of the elements commonly found in lead alloys, zinc and bismuth aggravate corrosion in most circumstances, while additions of copper, tellurium, antimony, nickel, silver, tin, arsenic and calcium may reduce corrosion resistance only slightly, or even improve it depending on the service conditions. Alloying elements that are of increasing importance are calcium especially in maintenance-free battery alloys and selenium, or sulphur combined with copper as nucleants in low antimony battery alloys. Other elements of interest are indium in anodesaluminium in batteries and selenium in chemical lead as a grain refiner ". 

Rare earth elements, with relatively high thermal neutron activation cross-sections, have been tested or considered as tagging species for this purpose. At GA (Ref 8), preliminary expts were conducted with 0.38 cal ammo using dysprosium (Dy) and europium (Eu) deposited on the wall of the cartridge case and in the gunpowder, and Dy, hoKnium (Ho) and indium (In) in the primer. 

In addition, it should be possible to extend the range of compounds to include aluminum and indium. In principle, there are no compelling reasons why these analogues of the currently known gallium species should not exist. The aluminum compounds would be of particular interest as calculations on the neutral frans-bent HAlAlH model species indicate a bond strength of 10 kcal moP which is over three times higher than that calculated... 

Indium, in Group 13, has three valence electrons. The configurations show three electrons with a — 5, so the configuration is consistent with the valence electron count. 

Indium (In) is a relatively rare element that never occurs as a free metal. It is usually found in a compound that contams 70.48% In and 29.52% S. What is the empirical formula for this compound ... 

In 1991, Li and Chan reported the use of indium to mediate Barbier-Grignard-type reactions in water (Eq. 8.49).108 When the allylation was mediated by indium in water, the reaction went smoothly at room temperature without any promoter, whereas the use of zinc and tin usually requires acid catalysis, heat, or sonication. The mildness of the reaction conditions makes it possible to use the indium method to allylate a methyl ketone in the presence of an acid-sensitive acetal functional group (Eq. 8.50). Furthermore, the coupling of ethyl 2-(bromomethyl)acrylate with carbonyl compounds proceeds equally well under the same reaction conditions, giving ready access to various hydroxyl acids including, for example, sialic acids. 

The combination of 2-halomethyl-3-halo-l-propene with carbonyl compounds mediated by indium in water generated / /.v-allylation... 

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