germánium

Germánium (germanium) is a chemical element with the symbol Ge and atomic number 32. It is a metalloid in group 14 of the periodic table, displaying properties between metals and nonmetals. Germanium occurs naturally in trace amounts and is obtained mainly as a byproduct of zinc ore processing and, to a lesser extent, coal.

Dmitri Mendeleev predicted an eka-silicon in 1871. Germanium was discovered in 1886 by Clemens Winkler, who isolated a new element in a mineral sample from Germany and named it after the country.

Germanium is a brittle, lustrous gray-white solid. It crystallizes in the diamond cubic form. It has a melting point of about 938°C and a boiling point near 2,900°C. Pure germanium is a poor conductor, but it becomes a good semiconductor when doped with other elements.

Crustal abundance is low, roughly a few milligrams per kilogram. It is commonly recovered from zinc sulfide concentrates and from certain coal deposits. Major producers have included China, Russia, and the United States.

Germanium is valued for its semiconductor properties and is used in high-speed electronics, fiber optics, and infrared optics. It is used in silicon–germanium alloys to tune electronic properties and in detectors and solar applications. The radioactive isotope Ge-68 is used to supply Ga-68 for PET imaging.

Germanium has five stable isotopes: Ge-70, Ge-72, Ge-73, Ge-74, and Ge-76. In addition, Ge-68 is a used radioisotope. Elemental germanium has relatively low toxicity, but several germanium compounds can be hazardous; appropriate precautions are advised.