Germanium, the first element in the periodic table named after a country, has the chemical symbol Ge, the atomic number 32, and is a lustrous metalloid in the carbon group. Germanium is chemically similar to tin and silicon and has the same crystal structure as diamond. A rare, silver-colored semiconductor metal that is used in infrared technology, fiber optic cables, and solar cells, Germanium’s unique characteristics include its transparency to near-infrared electromagnetic radiation (at wavelengths between 1600-1800 nanometers), a high refractive index, and its low optical dispersion.
Beyond the basics above, what else should we know about germanium? Check out the 20 interesting facts below!
- 1869: Demitri Mendeleev predicted the existence of element number 32, which he named eka-silicon, after he noticed a gap between silicon and tin in his periodic table.
- 1886: Chemist Clemens A. Winkler discovered and isolated the element germanium from the rare mineral argyrodite (Ag8GeS6). Analysis indicated the sample contained 73 – 75% silver, 17 – 18% sulfur, 0.2% mercury, and 6 – 7% a new element. He named the new element after his homeland, Germany.
- During the 1920s, research into the electrical properties of germanium resulted in the development of high purity, single-crystal germanium.
- 1945: Germanium’s value was recognized during World War II when it was used in high-resolution radar receivers. The first germanium transistor was invented shortly afterward.
- 1947: The first commercial application for germanium came after the war, following the invention of transistors by John Bardeen, Walter Brattain, and William Shockley at Bell Labs in December of 1947. In the years following, germanium-containing transistors found their way into telephone switching equipment, military computers, hearing aids and portable radios.
- The first Voyager space exploration missions launched in the 1970s relied on power produced by silicon-germanium (SiGe) photovoltaic cells (PVCs). Germanium-based PVCs are still critical to satellite operations.
- Interest in far IR detectors began in the 1980s, leading to increased demand for germanium. NASA was interested in far IR detectors because this region of the electromagenetic spectrum contained valuable information about star formation, interstellar dust, planet formation, and accretion disks around young stars.
- The development and expansion or fiber optic networks in the 1990s led to increased demand for germanium, which is used to form the glass core of fiber optic cables.
- By 2000, high-efficiency PVCs and light-emitting diodes (LEDs) dependent upon germanium substrates had become large consumers of the element.
- Germanium metal import sources to the United States (2014–17): China, 58%; Belgium, 26%; Germany, 7%; Russia, 6%; and other, 3%.
- In May 2018, the U.S. Department of the Interior, in coordination with other executive branch agencies, published a list of 35 critical minerals (83 FR 23295), including germanium. This list was developed to serve as an initial focus, pursuant to Executive Order 13817, ‘‘A Federal Strategy to Ensure Secure and Reliable Supplies of Critical Minerals” (82 FR 60835).
- The available resources of germanium are associated with certain zinc and lead-zinc-copper sulfide ores. The amount of germanium potentially recoverable from coal fly ash is essentially unlimited, but the commercial recovery of the metal is not currently viable to the extent that it has replaced germanium recovered from primary sources.
- Germanium use is essential in electronics such as in-phase memory chips, semiconductor, and solar applications, fiber-optic systems, infrared optics and detectors, polymerization catalysts, camera and microscope lenses, glass in satellite systems and fire alarms, LED production, electric guitar amplifiers, and various medical applications.
- According to the U.S. Geological Survey, approximate percentages of the uses of germanium are: 30 percent for infrared (IR) optics, including detectors; 20 percent fiber optics used in communications; 20 percent polyethylene terephthalate used in a variety of products such as cloth fibers, food containers, and resins; 15 percent for electronics and solar cells for solar panels; and 5 percent for phosphors, metallurgy, and organics including medications.
- Germanium is metalloid, which means it has properties of both metals and nonmetals. Other metalloids on the periodic table are boron, silicon, arsenic, antimony, tellurium, and polonium.
- Germanium is one of the few elements that expands when it freezes. Others include gallium, silicon, bismuth and antimony.
- Germanium abundance in the Earth’s crust: 1.5 parts per million by weight, 0.42 parts per million by moles. Germanium abundance in the solar system: 200 parts per billion by weight, 3 parts per billion by moles.
- Naturally occurring germanium is a mixture of five isotopes found in the percentages shown: 70Ge (21.2%), 72Ge (27.7%), 73Ge (7.7%), 74Ge (35.9%) and 76Ge (7.4%).
- China is the leading global producer of germanium.
- Worldwide, about 30% of the total germanium consumed is produced from recycled materials.