What is Germanium
Germanium (pronunciation: jer-MAY-ni-em) is a shiny, silvery element classified as a metalloid and represented by the chemical symbol Ge [1, 2]. As a relatively inactive element, germanium does not react with oxygen at 20°C and is insoluble in water but its compound, germanium dioxide, is slightly soluble in water .
Its five stable isotopes, germanium-70, germanium-72, germanium-73, germanium-74, and germanium-76, occur naturally out of which germanium-74 is the most common with a natural abundance of around 36% . Germanium-76 is slightly radioactive with a half-life period of 1.6 X 1021 years and a natural abundance of around 7% [1, 4]. It also has more than 27 artificially produced radioisotopes whose atomic mass ranges from 58-89 .
Where is Germanium Found
Germanium rarely occurs as pure ore compounds and is found in small amounts in minerals like argyrodite and germanite . While it can also be obtained from zinc ores, flue dust from zinc smelting is a commercial source of germanium . Moreover, it can be recovered from coal combustion by-products .
The top 3 germanium producing countries include China, Russia, and Germany .
Origin of its Name: It is named after ‘Germania’, the Latin word for Germany .
Who discovered it: The German chemist Clemens A. Winkler is known to be the discoverer of germanium .
When and How was it Discovered
In September 1885, an unusual mineral ore was found by a miner who was working in the Himmelsfürst mine in the Freiberg district of Germany . He passed it to Albin Weisbach, the German mineralogist who confirmed it was a new mineral, which we now know as Argyrodite (Ag8GeS6) . His colleague Clemens Winkler analyzed the new mineral and found that it consisted of 18% sulfur, 75% silver, while the remaining 7% could not be explained [1, 5]. By February 1886, Winkler realized that it was a new element and named it germanium, the properties of which were earlier predicted by the Russian chemist Dmitri Mendeleev [1, 5].
|Atomic number||32 |
|CAS number||7440-56-4 |
|Position in the periodic table||Group||Period||Block|
|14 ||4 ||p |
Properties and Characteristics of Germanium
|Relative atomic mass||72.630 |
|Atomic mass||72.630 amu |
|Molar mass||72.6400 g/mol |
|Allotropes||α-Ge, β-Ge |
|Color||Silvery-white [1, 6]|
|Melting point/freezing point||938.25 °C, 1720.85 °F |
|Boiling point||2833 °C, 5131 °F |
|Density||5.3234 g cm-3 |
|State of matter at room temperature (solid/liquid/gas)||Solid [1, 5]|
|– Brinell||7273.4 MPa |
|– Mohs||6 |
|– Vickers||8012.03 MPa |
|Electrical conductivity||2000 S/m |
|Charge||+4, +2 |
|Thermal (heat) conductivity||60 W/(m K) |
|Specific heat||320 J kg-1 K-1 |
|Bulk modulus||Unknown |
|Shear modulus||Unknown |
|Young’s modulus||Unknown |
|– Temperature (K)||400||600||800||1000||1200||1400||1600||1800||2000||2200||2400|
|– Pressure (Pa)||–||–||–||–||–||–||–||–||–||–||–|
|Oxidation states||4 |
|Isotopes||Isotope||Mass||Abundance (%)||Half-life||Mode of decay|
|73Ge||72.923||7.75||> 1.8 X 1023 y||β-|
|76Ge||75.921||7.73||1.6 X 1021 y||β-β-|
Atomic Data of Germanium (Element 32)
|Valence electrons||4 |
|– n||4 |
|– ℓ||1 |
|– mℓ||0 |
|– ms||+1/2 |
|Electron configuration (noble gas configuration)||[Ar] 3d104s24p2 |
|– Number of electrons||32 |
|– Number of neutrons||42 |
|– Number of protons||32 |
|Radius of Atom|
|– Atomic radius||2.11 Å |
|– Covalent radius||1.20 Å |
|Electronegativity (Pauling-scale)||2.01 |
|Electron affinity||118.939 kJ mol-1 |
|Ionization energy (kJ mol-1)||1st||2nd||3rd||4th||5th||6th||7th||8th|
What is it Used for
- Pure germanium was usually doped with gallium, arsenic, or other elements for use as a semiconductor in transistors and integrated circuits of electronic applications [1, 5]. Today, it has been replaced by other semiconductors .
- Because of its high dispersion and refraction index, germanium is commonly used in objective lenses for microscopes and wide-angle lenses for camera .
- It is added to alloys, including silver, for stopping it from tarnishing . It can as well be used as a catalyst and in fluorescent lamps [1, 5].
- Since germanium and its oxide are transparent in infrared wavelength, they make excellent infrared optical material and are utilized in infrared spectroscopes .
- Organic germanium, sold as supplements, is believed to be useful for promoting a healthy immune system, destroying free radicals, and supplying oxygen in the body . It is claimed to be a remedy for health conditions like allergies, arthritis, HIV, cancer, and asthma .
- It is used in making solar cells that are placed in solar panels .
Is Germanium Toxic
The element 32 is considered non-toxic . Although some of its compounds are slightly toxic in mammals, they are known for their anti-bacterial properties for which researchers are now looking into their probable use in medications .
- Germanium’s graphical representation features an image of a transistor, which indicates the early use of the element .
- Being a metalloid, germanium has the properties of both nonmetals and metals .
- Like water, germanium is known to expand on freezing .
- It was commonly used in high-resolution radar during the Second World War .
The cost of pure germanium is around $3.60 per gram, and in bulk, its price is around $1.20 per gram .