D. W. Thomas, T. Mahmood, Charles B. Lindhal
Jul 15, 2011
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Abstract
Germanium is a semiconducting metalloid element found in Group 14 (IVA), Period 4 of the Periodic Table. Although it looks like a metal, it has a diamond cubic crystal structure and is fragile like glass. Its electrical resistivity is about midway between that of metallic conductors and good electrical insulators. The first significant use was in solid-state electronics, and, using germanium, the transistor was invented. The entire modern field of semiconductors owes it development to the early successful use of germanium. Germanium is used for optical fiber production, as polymerization catalysts, in infrared optics, in electronic and solar applications, and in other miscellaneous markets. Germanium usually occurs widely dispersed in minerals. Most germanium production has been from zinc smelters and copper smelters. Germanium also occurs in significant concentrations in many coals around the world. Germanium is quite stable in air up to 400°C, where slow oxidation begins. The metal resists concentrated acid and alkali. Many Ge alloys have been prepared and studied. No mineral is mined solely for its germanium content. Almost all of the Ge recovered worldwide is a by-product of other mining. Germanium compounds generally have a low order of toxicity. Keywords: Occurrence; Sources; Properties; Grades; Enviornmental aspects; Health and Safety; Recycling; Analytical Methods; Uses; Manufacture; Economics; Halides; Oxides; Germanates; Germanides; Germanes; Organogermanium compounds; Alloys; Ores; Scrap; Telecommunications; Optical fibers; Night-driving systems; Silver; Copper; Scrap