Germanium

Germanium is a major semiconductor material.   When doped with arsenic, gallium, or other elements, it is used as a component in transistors.   Germanium is also used in alloys, a phosphor in fluorescent lamps and a catalyst.   Germanium and germanium oxide are used in infrared spectroscopes and infrared detectors.   Germanium oxide's high index of refraction makes it useful in glass used in camera and microscope lenses. ^{Lide 4-12}

Germanium was discovered in 1886 by Clemens Winkler, a German chemist.   It is found in argyrodite, a sulfide of germanium and silver, in germanite, in the dust of zinc smelters and in coal.   Germanium is isolated from other metals by fractional distillation of its volatile tetrachloride, which is then hydrolyzed to produce germanium dioxide, GeO₂, which is then reduced to obtain pure germanium. ^{Lide 4-12}