Introduction to Germanium
The element germanium is a lustrous and brittle metalloid in the carbon group. It is visually similar to silicon and reacts with oxygen similar to silicon. It’s also rare in high concentrations. Discovered later in history, germanium is now used for optics and electronics.
Ten Interesting & Fun Facts About Germanium
- Two decades before its discovery, Dmitri Mendeleev predicted the existence of germanium based on its position on the periodic table. He called the element ekasilicon.
- Germanium was almost named Neptunium in honor of Neptune’s discovery in 1846. However, the name was given to another element. The current Neptunium is not this original element.
- Germanium is in effects pedals that create the fuzz tone in early rock and roll.
- Alloys containing germanium prevent tarnish, as well as hardening, of sterling silver.
- Refining produces germanium with an impurity of 1 part in 1010, one of the purest materials ever found.
- An alloy of germanium, uranium, and rhodium was the first material to become a superconductor when exposed to a strong electromagnetic field in 2005.
- Germanium is one of the only elements that expands when it freezes, in addition to others such as gallium, silicon, and bismuth.
- It is a catalyst that produces certain plastics.
- Germanium didn’t become useful until 1945 when its semiconducting properties were discovered, nearly 60 years after its initial discovery.
- The half-life of a radioactive germanium isotope is over 100 billion times the age of the universe.
Element Germanium in the Periodic Table
Germanium, atomic symbol Ge, has an atomic number of 32, and lies in group 14, on the periodic table, below silicon and to the left of arsenic. This element has four valence electrons. This makes it less reactive because it would require more energy to lose or gain four electrons.
Germanium has an electronegativity of 2.01 (Pauling Scale). Germanium’s electron configuration is [Ar] 3d10 4s2 4p2. Other elements in the carbon family include carbon, silicon, lead, tin, and flerovium. It shares similar properties with its group.
Germanium in Health
Because germanium is usually only found in traces in ores and in electronic applications, it is unlikely to be ingested and has little to no health impact. Germanium supplements are an alternative medicine to treat leukemia and lung cancer. However, the FDA has publicly stated that germanium supplements actually present a health hazard for humans. Germanium is an injected alternative medicine that has caused renal dysfunction, hepatic steatosis, and peripheral neuropathy. Individuals have also died from this treatment, presenting high endogenous levels in their plasma and urine.
Germanium compounds have low toxicity for mammals, but can be toxic for certain bacteria. However, artificial compounds such as germanium tetrachloride and germane can irritate the eyes, skin, lungs, and throat.
Element Germanium’s Applications in Today’s World
What is Germanium Used For?
Germanium is in wide-angle camera lenses and microscopy due to its high index of refraction. Fiber optics use about 60% of germanium used in the USA. It is also useful in thermal imaging in military, night vision, and fire fighting purposes.
Silicon-germanium alloys are an important semiconductor. Germanium allows circuits to be much faster, in fact, wireless communication is beginning to use silicon-germanium alloys to replace gallium arsenide as a cheaper and more effective chip. Solar panels, Mars rovers, automobile headlights, and LCD screens use germanium.
Where Is Germanium Found?
Germanium is the by-product of sphalerite zinc ores. Silver, lead, and copper ores also contain germanium. Over 100 tons are produced annually, and a third of germanium is recycled. China, Russia, and the USA produce the most germanium.
When and How Was Germanium Discovered?
Clemens Winkler discovered the mineral argyrodite in a mine in 1885 near Freiberg, Saxony. Clemens Winkler then determined the mineral to be a combination of silver, sulfur, and a new element similar to antimony. The following year, Winkler isolated the element. Eventually, Winkler discovered its similarity to silicon and named it Germanium. The name comes from the Latin word, Germania, a name given in honor of Winkler’s homeland.
Germanium Chemistry – Compounds, Reactions, Oxidation States, Isolation
Chemical Properties of Germanium Element
Germanium oxidizes at 250 C to form GeO2. It is insoluble in dilute acids and alkalis, but reacts violently with molten alkalis to create germanates.
Here are a few common germanium compounds and their uses:
- GeO2, also called the salt of germanium, is the main source of germanium that forms as a result of the oxidation of elemental germanium. It is most commonly used for optics and has low toxicity.
- Though not well characterized, germanium dioxide reacts with germanium metal, forming germanium monoxide.
- This compound is a white crystalline solid. Clemens Winkler discovered germanium disulfide because it doesn’t dissolve in aqueous acid. Hydrogen sulfide reacts with germanium tetrachloride in a solution of hydrochloric acid to create germanium disulfide. It also naturally occurs from the burning of some coal-mining waste.
- Bi4Ge3O12 has importance in particle and aerospace physics, nuclear medicine, geology, and other industries. It forms in crystals.
- GeCl4 is a colorless liquid with an acidic odor. It is increasingly used in the production of optics. It is an intermediate for the purification of germanium metal of GeO2.
- GeH4 burns in air to produce GeO2 and water. Jupiter’s atmosphere contains germane. Germane is weakly acidic and also used in the semiconductor industry. It is also highly toxic and flammable. Exposure can cause malaise, headaches, dizziness, fainting, vomiting, and kidney damage.
Isolation of Germanium
Roasting is a heating process that converts ore concentrates to oxides. This creates germanium dioxide and germanate in the dust produced. Germanates mixed with zinc and neutralized to isolate germanium dioxide as a precipitate. Germanium dioxide reacts with chlorine to create germanium tetrachloride which isolates from other compounds through distillation because of its low boiling point. Germanium chloride becomes purified and then hydrolyzed, forming pure GeO2. The remaining germanium dioxide can then react with hydrogen to produce the element germanium for optic and semiconductor production. Carbon reacts with germanium dioxide and then forms the element germanium, used for steel production.
Germanium Oxidation States
The most common oxidation state is +4. +2 is also common. The oxidation states +3 and +1 are rare.
Physical Properties of Element Germanium
Germanium is a brittle, silver, and metallic semiconductor.
- Symbol: Ge
- Melting point: 938.25°C
- Boiling point: 2833°C
- Density (g cm−3): 5.323
- Atomic mass: 72.64
- Atomic number: 32
- Electronegativity (Pauling Scale): 2.01
- Classification: Group 14 Metalloid
- Crustal abundance (ppm):
- Electron configuration: [Ar] 3d10 4s2 4p2
- Key Isotopes: 68Ge, 70Ge, 71Ge, 72Ge, 73Ge, 74Ge, 76Ge
- Found naturally in the minerals: Sphalerite, Argyrodite
- Toxicity: Low
Where Can I Buy Elemental Germanium?
Websites, such as Nova Elements, sell 1 gram samples of purified germanium metal for 9,90 euros, or around $10.