Germanium is a semimetal or metalloid that is an important semiconductor in electronics. Because it is relatively uncommon in nature, it was discovered later than most elements near it on the periodic table. The element has atomic number 32 and element symbol Ge.
Fast Facts: The Element Germanium
- Element Name: Germanium
- Element Symbol: Ge
- Atomic Number: 32
- Atomic Weight: 72.630
- Classification: Metalloid
- State of Matter: Solid
- Name Origin: The name honors Winkler’s homeland of Germany
- Discovered By: Predicted by Mendeleev in 1869, discovered by Clemens Winkler in 1886
- Electron Configuration: [Ar] 3d10 4s2 4p2
- Group: 14 (carbon group)
- Period: 4
- Block: p-block
History
Dmitri Mendeleev predicted the existence of germanium in his 1869 periodic table. He called the undiscovered element ekasilicon. Clemens Winkler discovered the element in 1886 in a new mineral named argyrodite. Winkler’s analysis showed that the mineral consisted of silver, sulfur, and some new element that seemed similar to antimony.
How Germanium Got Its Name
Winkler wanted to name his new element neptunium, after the recently discovered planet. However, the name was already proposed for another element (which was also not the element known as neptunium today). So, Winkler went with the name germanium, in honor of his home country of Germany.
Germanium Uses
While best-known for its use as a semiconductor, germanium has many uses. Its main application is in fiber optics and infrared optics. It also finds use as a polymerization catalyst, in solar cell, electronics, alloys, phosphors, and in medicine for chemotherapy.
Germanium Isotopes
Germanium occurs as a mixture of five natural isotopes: 70Ge, 72Ge, 73Ge, 74Ge, and 76Ge. Essentially, these are all stable isotopes, since 76Ge is only very slightly radioactive, with a half-life of 1.78×1021 years. The most abundant isotope is 74Ge, accounting for 36% of the element. To date, there are at least 27 radioactive isotopes that range from atomic mass 58 to 89.
Sources of Germanium
Germanium forms via nucleosynthesis in stars. The element’s abundance in the Earth’s crust is about 1.6 ppm. Minerals that contain germanium include argyrodite, germanite, sphalerite, briartite, and renierite. Some zinc/copper ores and coal seams contain sufficient germanium that extraction is affordable. China, Russia, and the United States produce most of the world’s germanium.
Health Effects
Germanium is not an essential nutrient for either animal or plant life. Because the element is relatively rare, it has minimal health effects in the environment. However, some germanium compounds are toxic. Germanium chloride and germane (GeH4) are skin and mucous membrane irritants.
While germanium supplements are available as an alternative medicine treatment for conditions like lung cancer and leukemia, there is insufficient evidence that they are effective. At the same time, some data indicates these supplements are toxic to the nervous system, live, and kidneys. Some germanium compounds have low toxicity to mammals, but high toxicity to some bacteria.
Interesting Germanium Facts
Here are additional interesting facts about the element germanium:
- There weren’t many uses for germanium until 1945, when its semiconducting properties were discovered.
- While germanium opened the doors for the electronics industry, it has largely been replaced by silicon, which has similar properties and is readily available.
- Germanium is an amphoteric oxide. That is, is has both negative and positive oxidation states.
- It has the same crystal structure as a diamond (face-centered diamond cubic).
- Pure germanium spontaneously extrudes “whiskers”, which lead to shorts and failures of old transistors and diodes.
- Precious metals in jewelry increasingly include germanium because it increases hardening and tarnish resistance, while decreasing firescale.
- When germanium oxide is the catalyst for polymerizing polyethylene terephthalate (PET), it produces especially brilliant polyester. Bottles made from the plastic are particularly attractive in Japanese markets, although they are not used in the United States.
- Gas chromatography columns replace silica (SiO2) with germanium dioxide (GeO2) for some applications because of the similarities between the chemical properties of the two compounds.
- Airport security scanners often incorporate germanium semiconductor detectors because they excel at detecting radiation sources.
- Spintronics is an upcoming tech that uses germanium in solid state devices and quantum computing.
Physical Data
State at room temperature: Solid
Appearance: Metallic grayish white
Density: 5.323 g/cc (20 °C)
Melting Point: 1211.40 K (938.25 °C, 1720.85 °F)
Boiling Point: 3106 K (2833 °C, 5131 °F)
Heat of Fusion: 36.94 kJ/mol
Heat of Vaporization: 334 kJ/mol
Molar Heat Capacity: 23.222 J/mol·K
Atomic Data
Oxidation States: −4, −3, −2, −1, 0, +1, +2, +3, +4
Electronegativity: 2.01
Atomic Radius: 1.22 Å
Covalent Radius: 1.22 Å
Van der Waals Radius: 2.11 Å
First Ionization Energy: 762 kJ/mol
Second Ionization Energy: 1537.5 kJ/mol
Third Ionization Energy: 3302.1 kJ/mol
References
- Crisp, D.; Pathare, A.; Ewell, R. C. (2004). “The performance of gallium arsenide/germanium solar cells at the Martian surface”. Acta Astronautica. 54 (2): 83–101. doi:10.1016/S0094-5765(02)00287-4
- Gerber, G. B.; Léonard, A. (1997). “Mutagenicity, carcinogenicity and teratogenicity of germanium compounds”. Regulatory Toxicology and Pharmacology. 387 (3): 141–146. doi:10.1016/S1383-5742(97)00034-3
- Frenzel, Max; Ketris, Marina P.; Gutzmer, Jens (2013-12-29). “On the geological availability of germanium”. Mineralium Deposita. 49 (4): 471–486. doi:10.1007/s00126-013-0506-z
- Weast, Robert (1984). CRC, Handbook of Chemistry and Physics. Boca Raton, Florida: Chemical Rubber Company Publishing. pp. E110. ISBN 0-8493-0464-4.
- Winkler, Clemens (1887). “Germanium, Ge, a New Nonmetal Element”. Berichte der Deutschen Chemischen Gesellschaft (in German). 19 (1): 210–211. doi:10.1002/cber.18860190156