Electrical indium compounds

Table. 1-88 Carrier concentrations n-, and electrical conductivity a of indium compounds...

Indium is a soft malleable, silvery white metal. Due to its low friction properties, it is used in bearing alloys. Certain indium compounds have unique semiconductor properties. Films of ITO, indium-tin oxide (80% In Oj), are transparent to visible light but not for infrared light. In addition they have good electrical conductivity. The electrical conductivity of the thin coating is utilized on windshields for railway locomotives and airplanes to make it possible to warm them up with electric current for defogging. 

Spray Pyrolysis. In spray pyrolysis, a chemical solution is sprayed on a hot surface where it is pyrolyzed (decomposed) to give thin films of either elements or, more commonly, compounds (22). Eor example, to deposit CdS, a solution of CdCl plus NH2CSNH2 (thiourea) is sprayed on a hot surface. To deposit Iu202, InCl is dissolved in a solvent and sprayed on a hot surface in air. Materials that can be deposited by spray pyrolysis include electrically conductive tin—oxide and indium/tin oxide (ITO), CdS, Cu—InSe2, and CdSe. Spray pyrolysis is an inexpensive deposition process and can be used on large-area substrates. 

Application of zinc as a sacrificial anode often overcomes the difficulties with activation of zinc in the Reformatsky reaction and the problems with uncontrolled exothermic reactions. When zinc or indium is employed for the reaction, the amount of electricity used is less than the theoretical, and this suggests that the anode acts as activated metal and reacts with the bromo compound [175]. 

Only boron, the first element in Group 13, is a metalloid. The other Group 13 elements—almninum (Al), gaUimn (Ga), indium (In), and thal-limn (Tl)—are metals. None of the metals are as active as the metals in Groups 1 and 2, but they re good conductors of heat and electricity. They are silvery in appearance and fairly soft. Group 13 metals tend to share electrons rather than form ionic compoimds in this respect, they resemble boron. Their valence configuration is and they exhibit the 3+ oxidation number in most of their compounds. 

In the indium-sulfur system the phases InS1, In S72, and three allotropic forms of In2S33 4 5 have been identified and their structures analyzed. All of these compounds have been prepared by conventional methods, that is, direct combination or transport reaction techniques. By using molten tin as a solvent, a new metal-rich combination was obtained. The material is electrically insulating and diamagnetic at room temperature. 

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