Germanium

Germanium is a chemical element; it has symbol

Germanium, 32Ge
Ge and atomic number 32. It is lustrous, hard-
brittle, grayish-white and similar in appearance to
silicon. It is a metalloid (more rarely considered a
metal) in the carbon group that is chemically
similar to its group neighbors silicon and tin.
Like silicon, germanium naturally reacts and
forms complexes with oxygen in nature.

Because it seldom appears in high concentration,

germanium was found comparatively late in the
discovery of the elements. Germanium ranks 50th
in abundance of the elements in the Earth's crust.
In 1869, Dmitri Mendeleev predicted its Germanium
existence and some of its properties from its Pronunciation /dʒɜːrˈmeɪniəm/ ​
position on his periodic table, and called the (jur-MAY-nee-əm)
element ekasilicon. On February 6, 1886, Appearance grayish-white
Clemens Winkler at Freiberg University found
the new element, along with silver and sulfur, in Standard atomic weight Ar°(Ge)
the mineral argyrodite. Winkler named the 72.630 ± 0.008[1]
element after Germany, his country of birth. 72.630 ± 0.008 (abridged)[2]
Germanium is mined primarily from sphalerite
Germanium in the periodic table
(the primary ore of zinc), though germanium is
also recovered commercially from silver, lead, Si
↑
and copper ores. Ge
↓
Sn
Elemental germanium is used as a semiconductor
gallium ← germanium → arsenic
in transistors and various other electronic
devices. Historically, the first decade of Atomic number (Z) 32
semiconductor electronics was based entirely on Group group 14 (carbon group)
germanium. Presently, the major end uses are Period period 4
fibre-optic systems, infrared optics, solar cell
Block p-block
applications, and light-emitting diodes (LEDs).
Germanium compounds are also used for Electron [Ar] 3d10 4s2 4p2
polymerization catalysts and have most recently configuration
found use in the production of nanowires. This Electrons per shell 2, 8, 18, 4
element forms a large number of Physical properties
organogermanium compounds, such as
Phase at STP solid
tetraethylgermanium, useful in organometallic
chemistry. Germanium is considered a Melting point 1211.40 K ​(938.25 °C, ​
1720.85 °F)
technology-critical element.[11]
Boiling point 3106 K ​(2833 °C, ​5131 °F)
Germanium is not thought to be an essential Density (at 20° C) 5.327 g/cm3[3]
element for any living organism. Similar to when liquid (at m.p.) 5.60 g/cm3
silicon and aluminium, naturally-occurring
Heat of fusion 36.94 kJ/mol
germanium compounds tend to be insoluble in
water and thus have little oral toxicity. However, Heat of vaporization 334 kJ/mol

synthetic soluble germanium salts are Molar heat capacity 23.222 J/(mol·K)
nephrotoxic, and synthetic chemically reactive Vapor pressure
germanium compounds with halogens and P (Pa) 1 10 100 1k 10 k 100 k
hydrogen are irritants and toxins.
at T (K) 1644 1814 2023 2287 2633 3104

Atomic properties
History Oxidation states common: −4, +2, +4
−3,[4] −2,[4] −1,[4] 0,[5] +1,[6]
+3[6]
Electronegativity Pauling scale: 2.01
Ionization energies 1st: 762 kJ/mol
Prediction of germanium, "?
=70" (periodic table 1869) 2nd: 1537.5 kJ/mol
3rd: 3302.1 kJ/mol
In his report on The Periodic Law of the
Atomic radius empirical: 122 pm
Chemical Elements in 1869, the Russian chemist
Covalent radius 122 pm
Dmitri Mendeleev predicted the existence of
several unknown chemical elements, including Van der Waals 211 pm
one that would fill a gap in the carbon family, radius
located between silicon and tin.[12] Because of its
position in his periodic table, Mendeleev called it
Spectral lines of germanium
ekasilicon (Es), and he estimated its atomic
Other properties
weight to be 70 (later 72).
Natural occurrence primordial
In mid-1885, at a mine near Freiberg, Saxony, a Crystal structure f​ace-centered diamond-cubic
new mineral was discovered and named (cF8)
argyrodite because of its high silver
Lattice constant a = 565.774 pm
content.[note 1] The chemist Clemens Winkler
(at 20 °C)[3]
analyzed this new mineral, which proved to be a
combination of silver, sulfur, and a new element.
Thermal expansion 5.79 × 10−6/K (at 20 °C)[3]
Winkler was able to isolate the new element in
1886 and found it similar to antimony. He Thermal 60.2 W/(m⋅K)
initially considered the new element to be eka- conductivity

antimony, but was soon convinced that it was Electrical resistivity 1 Ω⋅m (at 20 °C)
instead eka-silicon.[14][15] Before Winkler Band gap 0.67 eV (at 300 K)
published his results on the new element, he Magnetic ordering diamagnetic[7]
decided that he would name his element
Molar magnetic −76.84 × 10−6 cm3/mol[8]
neptunium, since the recent discovery of planet
susceptibility
Neptune in 1846 had similarly been preceded by
mathematical predictions of its existence.[note 2] Young's modulus 103 GPa[9]
However, the name "neptunium" had already Shear modulus 41 GPa[9]
been given to another proposed chemical element Bulk modulus 75 GPa[9]
(though not the element that today bears the Speed of sound 5400 m/s (at 20 °C)
name neptunium, which was discovered in thin rod
1940).[note 3] So instead, Winkler named the new
Poisson ratio 0.26[9]
element germanium (from the Latin word,
Mohs hardness 6.0
Germania, for Germany) in honor of his
homeland.[15] Argyrodite proved empirically to CAS Number 7440-56-4
be Ag8GeS6. Because this new element showed History
some similarities with the elements arsenic and Naming after Germany, homeland of
antimony, its proper place in the periodic table the discoverer
was under consideration, but its similarities with
Prediction Dmitri Mendeleev (1869)
Dmitri Mendeleev's predicted element
"ekasilicon" confirmed that place on the periodic Discovery Clemens Winkler (1886)

table.[15][22] With further material from 500 kg of Isotopes of germanium

ore from the mines in Saxony, Winkler confirmed
Main isotopes[10] Decay
the chemical properties of the new element in
1887.[14][15][23] He also determined an atomic abun­dance half-life (t1/2) mode pro­duct
weight of 72.32 by analyzing pure germanium 68
Ge synth 270.8 d ε 68
Ga
tetrachloride (GeCl4), while Lecoq de
70
Boisbaudran deduced 72.3 by a comparison of Ge 20.5% stable
the lines in the spark spectrum of the element.[24] 71
Ge synth 11.468 d ε 71
Ga

Winkler was able to prepare several new 72

Ge 27.4% stable
compounds of germanium, including fluorides, 73
Ge 7.76% stable
chlorides, sulfides, dioxide, and
tetraethylgermane (Ge(C2H5)4), the first 74
Ge 36.5% stable
organogermane. [14] The physical data from those 76
Ge 7.75% 1.78×1021 y β−β− 76
Se
compounds—which corresponded well with
Mendeleev's predictions—made the discovery an
important confirmation of Mendeleev's idea of element periodicity. Here is a comparison between the
prediction and Winkler's data:[14]

Ekasilicon Germanium
Property Mendeleev Winkler
prediction (1871) discovery (1887)

atomic mass 72.64 72.63

density (g/cm3) 5.5 5.35

melting point (°C) high 947

color gray gray

oxide type refractory dioxide refractory dioxide

oxide density (g/cm3) 4.7 4.7

oxide activity feebly basic feebly basic

chloride boiling point (°C) under 100 86 (GeCl4)

chloride density (g/cm3) 1.9 1.9

Until the late 1930s, germanium was thought to be a poorly conducting metal.[25] Germanium did not
become economically significant until after 1945 when its properties as an electronic semiconductor were
recognized. During World War II, small amounts of germanium were used in some special electronic
devices, mostly diodes.[26][27] The first major use was the point-contact Schottky diodes for radar pulse
detection during the War.[25] The first silicon–germanium alloys were obtained in 1955.[28] Before 1945,
only a few hundred kilograms of germanium were produced in smelters each year, but by the end of the
1950s, the annual worldwide production had reached 40 metric tons (44 short tons).[29]

The development of the germanium transistor in 1948[30] opened the door to countless applications of
solid state electronics.[31] From 1950 through the early 1970s, this area provided an increasing market for
germanium, but then high-purity silicon began replacing germanium in transistors, diodes, and
rectifiers.[32] For example, the company that became Fairchild Semiconductor was founded in 1957 with
the express purpose of producing silicon transistors. Silicon has superior electrical properties, but it
requires much greater purity that could not be commercially achieved in the early years of semiconductor
electronics.[33]

Meanwhile, the demand for germanium for fiber optic communication networks, infrared night vision
systems, and polymerization catalysts increased dramatically.[29] These end uses represented 85% of
worldwide germanium consumption in 2000.[32] The US government even designated germanium as a
strategic and critical material, calling for a 146 ton (132 tonne) supply in the national defense stockpile in
1987.[29]

Germanium differs from silicon in that the supply is limited by the availability of exploitable sources,
while the supply of silicon is limited only by production capacity since silicon comes from ordinary sand
and quartz. While silicon could be bought in 1998 for less than $10 per kg,[29] the price of germanium
was almost $800 per kg.[29]

Characteristics
Under standard conditions, germanium is a brittle, silvery-white,[34] semiconductor. This form constitutes
an allotrope known as α-germanium, which has a metallic luster and a diamond cubic crystal structure,
the same structure as silicon and diamond.[32] In this form, germanium has a threshold displacement
energy of .[35] At pressures above 120 kbar, germanium becomes the metallic allotrope β-
germanium with the same structure as β-tin.[36] Like silicon, gallium, bismuth, antimony, and water,
germanium is one of the few substances that expands as it solidifies (i.e. freezes) from the molten
state.[36]

Germanium is a semiconductor having an indirect bandgap, as is crystalline silicon. Zone refining

techniques have led to the production of crystalline germanium for semiconductors that has an impurity
of only one part in 1010,[37] making it one of the purest materials ever obtained.[38] The first semi-
metallic material discovered (in 2005) to become a superconductor in the presence of an extremely strong
electromagnetic field was an alloy of germanium, uranium, and rhodium.[39]

Pure germanium is known to spontaneously extrude very long screw dislocations, referred to as
germanium whiskers. The growth of these whiskers is one of the primary reasons for the failure of older
diodes and transistors made from germanium, as, depending on what they eventually touch, they may
lead to an electrical short.[40]

Chemistry
Elemental germanium starts to oxidize slowly in air at around 250 °C, forming GeO2 .[41] Germanium is
insoluble in dilute acids and alkalis but dissolves slowly in hot concentrated sulfuric and nitric acids and
2−
reacts violently with molten alkalis to produce germanates ([GeO3] ). Germanium occurs mostly in the
oxidation state +4 although many +2 compounds are known.[42] Other oxidation states are rare: +3 is
found in compounds such as Ge2Cl6, and +3 and +1 are found on the surface of oxides,[43] or negative
oxidation states in germanides, such as −4 in Mg2Ge. Germanium cluster anions (Zintl ions) such as
Ge42−, Ge94−, Ge92−, [(Ge9)2]6− have been prepared by the extraction from alloys containing alkali
metals and germanium in liquid ammonia in the presence of ethylenediamine or a cryptand.[42][44] The
oxidation states of the element in these ions are not integers—similar to the ozonides O3−.

Two oxides of germanium are known: germanium dioxide (GeO2, germania) and germanium monoxide,
(GeO).[36] The dioxide, GeO2, can be obtained by roasting germanium disulfide (GeS2), and is a white
powder that is only slightly soluble in water but reacts with alkalis to form germanates.[36] The
monoxide, germanous oxide, can be obtained by the high temperature reaction of GeO2 with elemental
Ge.[36] The dioxide (and the related oxides and germanates) exhibits the unusual property of having a
high refractive index for visible light, but transparency to infrared light.[45][46] Bismuth germanate,
Bi4Ge3O12 (BGO), is used as a scintillator.[47]

Binary compounds with other chalcogens are also known, such as the disulfide (GeS2) and diselenide
(GeSe2), and the monosulfide (GeS), monoselenide (GeSe), and monotelluride (GeTe).[42] GeS2 forms as
a white precipitate when hydrogen sulfide is passed through strongly acid solutions containing
Ge(IV).[42] The disulfide is appreciably soluble in water and in solutions of caustic alkalis or alkaline
sulfides. Nevertheless, it is not soluble in acidic water, which allowed Winkler to discover the
element.[48] By heating the disulfide in a current of hydrogen, the monosulfide (GeS) is formed, which
sublimes in thin plates of a dark color and metallic luster, and is soluble in solutions of the caustic
alkalis.[36] Upon melting with alkaline carbonates and sulfur, germanium compounds form salts known as
thiogermanates.[49]

Four tetrahalides are known. Under normal conditions germanium

tetraiodide (GeI4) is a solid, germanium tetrafluoride (GeF4) a gas and the
others volatile liquids. For example, germanium tetrachloride, GeCl4, is
obtained as a colorless fuming liquid boiling at 83.1 °C by heating the
metal with chlorine.[36] All the tetrahalides are readily hydrolyzed to
hydrated germanium dioxide.[36] GeCl4 is used in the production of
organogermanium compounds.[42] All four dihalides are known and in
contrast to the tetrahalides are polymeric solids.[42] Additionally Ge2Cl6
Germane is similar to
methane.
and some higher compounds of formula GenCl2n+2 are known.[36] The
unusual compound Ge6Cl16 has been prepared that contains the Ge5Cl12
unit with a neopentane structure.[50]
Germane (GeH4) is a compound similar in structure to methane. Polygermanes—compounds that are
similar to alkanes—with formula GenH2n+2 containing up to five germanium atoms are known.[42] The
germanes are less volatile and less reactive than their corresponding silicon analogues.[42] GeH4 reacts
with alkali metals in liquid ammonia to form white crystalline MGeH3 which contain the GeH3−
anion.[42] The germanium hydrohalides with one, two and three halogen atoms are colorless reactive
liquids.[42]

The first organogermanium compound was synthesized

by Winkler in 1887; the reaction of germanium
tetrachloride with diethylzinc yielded tetraethylgermane
(Ge(C2H5)4).[14] Organogermanes of the type R4Ge
(where R is an alkyl) such as tetramethylgermane Nucleophilic addition with an
(Ge(CH3)4) and tetraethylgermane are accessed through organogermanium compound
the cheapest available germanium precursor germanium
tetrachloride and alkyl nucleophiles. Organic germanium
hydrides such as isobutylgermane ((CH3)2CHCH2GeH3) were found to be less hazardous and may be
used as a liquid substitute for toxic germane gas in semiconductor applications. Many germanium
reactive intermediates are known: germyl free radicals, germylenes (similar to carbenes), and germynes
(similar to carbynes).[51][52] The organogermanium compound 2-carboxyethylgermasesquioxane was first
reported in the 1970s, and for a while was used as a dietary supplement and thought to possibly have anti-
tumor qualities.[53]

Using a ligand called Eind (1,1,3,3,5,5,7,7-octaethyl-s-hydrindacen-4-yl) germanium is able to form a

double bond with oxygen (germanone). Germanium hydride and germanium tetrahydride are very
flammable and even explosive when mixed with air.[54]

Isotopes
70 72 73 74 76 76
Germanium occurs in five natural isotopes: Ge, Ge, Ge, Ge, and Ge. Of these, Ge is very
74
slightly radioactive, decaying by double beta decay with a half-life of 1.78 × 1021 years. Ge is the most
76
common isotope, having a natural abundance of approximately 36%. Ge is the least common with a
72
natural abundance of approximately 7%.[55] When bombarded with alpha particles, the isotope Ge will
77
generate stable Se, releasing high energy electrons in the process.[56] Because of this, it is used in
combination with radon for nuclear batteries.[56]

At least 27 radioisotopes have also been synthesized, ranging in atomic mass from 58 to 89. The most
68
stable of these is Ge, decaying by electron capture with a half-life of 270.95 days. The least stable is
60 61
Ge, with a half-life of 30 ms. While most of germanium's radioisotopes decay by beta decay, Ge and
64 + 84 87 −
Ge decay by β delayed proton emission.[55] Ge through Ge isotopes also exhibit minor β delayed
neutron emission decay paths.[55]

Occurrence
Germanium is created by stellar nucleosynthesis, mostly by the s-
process in asymptotic giant branch stars. The s-process is a slow
neutron capture of lighter elements inside pulsating red giant
stars.[57] Germanium has been detected in some of the most
distant stars[58] and in the atmosphere of Jupiter.[59]

Germanium's abundance in the Earth's crust is approximately

1.6 ppm.[60] Only a few minerals like argyrodite, briartite,
germanite, renierite and sphalerite contain appreciable amounts of
Renierite
germanium.[32][61] Only few of them (especially germanite) are,
very rarely, found in mineable amounts.[62][63][64] Some zinc–
copper–lead ore bodies contain enough germanium to justify extraction from the final ore concentrate.[60]
An unusual natural enrichment process causes a high content of germanium in some coal seams,
discovered by Victor Moritz Goldschmidt during a broad survey for germanium deposits.[65][66] The
highest concentration ever found was in Hartley coal ash with as much as 1.6% germanium.[65][66] The
coal deposits near Xilinhaote, Inner Mongolia, contain an estimated 1600 tonnes of germanium.[60]

Production
About 118 tonnes of germanium were produced in 2011 worldwide, mostly in China (80 t), Russia (5 t)
and United States (3 t).[32] Germanium is recovered as a by-product from sphalerite zinc ores where it is
concentrated in amounts as great as 0.3%,[67] especially from low-temperature sediment-hosted, massive
Zn–Pb–Cu(–Ba) deposits and carbonate-hosted Zn–Pb deposits.[68] A recent study found that at least
10,000 t of extractable germanium is contained in known zinc reserves, particularly those hosted by
Mississippi-Valley type deposits, while at least 112,000 t will be found in coal reserves.[69] In 2007 35%
of the demand was met by recycled germanium.[60]

While it is produced mainly from sphalerite, it is also found in silver, lead, and copper ores. Another
source of germanium is fly ash of power plants fueled from coal deposits that contain germanium. Russia
and China used this as a source for germanium.[71] Russia's deposits are located in the far east of Sakhalin
Island, and northeast of Vladivostok. The deposits in China are located mainly in the lignite mines near
Lincang, Yunnan; coal is also mined near Xilinhaote, Inner Mongolia.[60]

The ore concentrates are mostly sulfidic; they are converted to the oxides by heating under air in a
process known as roasting:

GeS2 + 3 O2 → GeO2 + 2 SO2

Some of the germanium is left in the dust produced, while the rest is converted to germanates, which are
then leached (together with zinc) from the cinder by sulfuric acid. After neutralization, only the zinc stays
in solution while germanium and other metals precipitate. After removing some of the zinc in the
precipitate by the Waelz process, the residing Waelz oxide is leached a second time. The dioxide is
obtained as precipitate and converted with chlorine gas or hydrochloric acid to germanium tetrachloride,
which has a low boiling point and can be isolated by distillation:[71]

GeO2 + 4 HCl → GeCl4 + 2 H2O

GeO2 + 2 Cl2 → GeCl4 + O2
Germanium tetrachloride is either hydrolyzed to the oxide (GeO2) or purified by
fractional distillation and then hydrolyzed.[71] The highly pure GeO2 is now suitable Year Cost
($/kg)[70]
for the production of germanium glass. It is reduced to the element by reacting it with
hydrogen, producing germanium suitable for infrared optics and semiconductor 1999 1,400
production: 2000 1,250

GeO2 + 2 H2 → Ge + 2 H2O 2001 890

2002 620
The germanium for steel production and other industrial processes is normally
2003 380
reduced using carbon:[72]
2004 600
GeO2 + C → Ge + CO2 2005 660
2006 880

Applications 2007 1,240

2008 1,490
The major end uses for germanium in 2007, worldwide, were estimated to be: 35% 2009 950
for fiber-optics, 30% infrared optics, 15% polymerization catalysts, and 15%
2010 940
electronics and solar electric applications.[32] The remaining 5% went into such uses
as phosphors, metallurgy, and chemotherapy.[32] 2011 1,625
2012 1,680

Optics 2013 1,875

The notable properties of germania (GeO2) are its high index of refraction and its low 2014 1,900

optical dispersion. These make it especially useful for wide-angle camera lenses, 2015 1,760
microscopy, and the core part of optical fibers.[73][74] It has replaced titania as the 2016 950
dopant for silica fiber, eliminating the subsequent heat treatment that made the fibers 2017 1,358
brittle.[75] At the end of 2002, the fiber optics industry consumed 60% of the annual
2018 1,300
germanium use in the United States, but this is less than 10% of worldwide
consumption.[74] GeSbTe is a phase change material used for its optic properties, 2019 1,240
such as that used in rewritable DVDs.[76] 2020 1,000

Because germanium is transparent in the infrared wavelengths, it is an important

infrared optical material that can be readily cut and polished into lenses and windows. It is especially
used as the front optic in thermal imaging cameras working in the 8 to 14 micron range for passive
thermal imaging and for hot-spot detection in military, mobile night vision, and fire fighting
applications.[72] It is used in infrared spectroscopes and other optical equipment that require extremely
sensitive infrared detectors.[74] It has a very high refractive index (4.0) and must be coated with anti-
reflection agents. Particularly, a very hard special antireflection coating of diamond-like carbon (DLC),
refractive index 2.0, is a good match and produces a diamond-hard surface that can withstand much
environmental abuse.[77][78]

Electronics
Germanium can be alloyed with silicon, and silicon–germanium alloys are rapidly becoming an important
semiconductor material for high-speed integrated circuits. Circuits using the properties of Si-SiGe
heterojunctions can be much faster than those using silicon alone.[79] The SiGe chips, with high-speed
properties, can be made with low-cost, well-established production techniques
of the silicon chip industry.[32]

High efficiency solar panels are a major use of germanium. Because

germanium and gallium arsenide have nearly identical lattice constant,
germanium substrates can be used to make gallium-arsenide solar cells.[80]
Germanium is the substrate of the wafers for high-efficiency multijunction
photovoltaic cells for space applications, such as the Mars Exploration Rovers, A typical single-mode
optical fiber.
which use triple-junction gallium arsenide on germanium cells.[81] High-
Germanium oxide is a
brightness LEDs, used for automobile headlights and to backlight LCD dopant of the core
screens, are also an important application.[32] silica (Item 1).

Germanium-on-insulator (GeOI) substrates are seen as a potential replacement 1. Core 8 µm

for silicon on miniaturized chips.[32] CMOS circuit based on GeOI substrates 2. Cladding
has been reported recently.[82] Other uses in electronics include phosphors in 125 µm
fluorescent lamps[37] and solid-state light-emitting diodes (LEDs).[32] 3. Buffer 250 µm
Germanium transistors are still used in some effects pedals by musicians who 4. Jacket 400 µm
wish to reproduce the distinctive tonal character of the "fuzz"-tone from the
early rock and roll era, most notably the Dallas Arbiter Fuzz Face.[83]

Germanium has been studied as a potential material for implantable bioelectronic sensors that are
resorbed in the body without generating harmful hydrogen gas, replacing zinc oxide- and indium gallium
zinc oxide-based implementations.[84]

Other uses
Germanium dioxide is also used in catalysts for polymerization in the
production of polyethylene terephthalate (PET).[85] The high brilliance of
this polyester is especially favored for PET bottles marketed in Japan.[85]
In the United States, germanium is not used for polymerization
catalysts.[32]

Due to the similarity between silica (SiO2) and germanium dioxide

(GeO2), the silica stationary phase in some gas chromatography columns
can be replaced by GeO2.[86]

In recent years germanium has seen increasing use in precious metal

alloys. In sterling silver alloys, for instance, it reduces firescale, increases
tarnish resistance, and improves precipitation hardening. A tarnish-proof
A PET bottle
silver alloy trademarked Argentium contains 1.2% germanium.[32]

Semiconductor detectors made of single crystal high-purity germanium

can precisely identify radiation sources—for example in airport security.[87] Germanium is useful for
monochromators for beamlines used in single crystal neutron scattering and synchrotron X-ray
diffraction. The reflectivity has advantages over silicon in neutron and high energy X-ray applications.[88]
Crystals of high purity germanium are used in detectors for gamma spectroscopy and the search for dark
matter.[89] Germanium crystals are also used in X-ray spectrometers for the determination of phosphorus,
chlorine and sulfur.[90]
Germanium is emerging as an important material for spintronics and spin-based quantum computing
applications. In 2010, researchers demonstrated room temperature spin transport[91] and more recently
donor electron spins in germanium has been shown to have very long coherence times.[92]

Strategic importance
Due to its use in advanced electronics and optics, Germanium is considered a technology-critical element
(by e.g. the European Union), essential to fulfill the green and digital transition. As China controls 60%
of global Germanium production it holds a dominant position over the world's supply chains.

On 3 July 2023 China suddenly imposed restrictions on the exports of germanium (and gallium),
ratcheting up trade tensions with Western allies. Invoking "national security interests," the Chinese
Ministry of Commerce informed that companies that intend to sell products containing germanium would
need an export licence. The products/compounds targeted are: germanium dioxide, germanium epitaxial
growth substrate, germanium ingot, germanium metal, germanium tetrachloride and zinc germanium
phosphide. It sees such products as "dual-use" items that may have military purposes and therefore
warrant an extra layer of oversight.

The new dispute opened a new chapter in the increasingly fierce technology race that has pitted the
United States, and to a lesser extent Europe, against China. The US wants its allies to heavily curb, or
downright prohibit, advanced electronic components bound to the Chinese market to prevent Beijing
from securing global technology supremacy. China denied any tit-for-tat intention behind the Germanium
export restrictions.[93][94][95]

Following China's export restrictions, Russian state-owned company Rostec announced an increase in
germanium production to meet domestic demand.[96]

Germanium and health

Germanium is not considered essential to the health of plants or animals.[97] Germanium in the
environment has little or no health impact. This is primarily because it usually occurs only as a trace
element in ores and carbonaceous materials, and the various industrial and electronic applications involve
very small quantities that are not likely to be ingested.[32] For similar reasons, end-use germanium has
little impact on the environment as a biohazard. Some reactive intermediate compounds of germanium
are poisonous (see precautions, below).[98]

Germanium supplements, made from both organic and inorganic germanium, have been marketed as an
alternative medicine capable of treating leukemia and lung cancer.[29] There is, however, no medical
evidence of benefit; some evidence suggests that such supplements are actively harmful.[97] U.S. Food
and Drug Administration (FDA) research has concluded that inorganic germanium, when used as a
nutritional supplement, "presents potential human health hazard".[53]

Some germanium compounds have been administered by alternative medical practitioners as non-FDA-
allowed injectable solutions. Soluble inorganic forms of germanium used at first, notably the citrate-
lactate salt, resulted in some cases of renal dysfunction, hepatic steatosis, and peripheral neuropathy in
individuals using them over a long term. Plasma and urine germanium concentrations in these
individuals, several of whom died, were several orders of magnitude greater than endogenous levels. A
more recent organic form, beta-carboxyethylgermanium sesquioxide (propagermanium), has not
exhibited the same spectrum of toxic effects.[99]

Certain compounds of germanium have low toxicity to mammals, but have toxic effects against certain
bacteria.[34]

Precautions for chemically reactive germanium compounds

While use of germanium itself does not require precautions, some of germanium's artificially produced
compounds are quite reactive and present an immediate hazard to human health on exposure. For
example, Germanium tetrachloride and germane (GeH4) are a liquid and gas, respectively, that can be
very irritating to the eyes, skin, lungs, and throat.[100]

See also
Germanene
Vitrain
History of the transistor

Notes
1. From Greek, argyrodite means silver-containing.[13]
2. Just as the existence of the new element had been predicted, the existence of the planet
Neptune had been predicted in about 1843 by the two mathematicians John Couch Adams
and Urbain Le Verrier, using the calculation methods of celestial mechanics. They did this in
attempts to explain the fact that the planet Uranus, upon very close observation, appeared
to be being pulled slightly out of position in the sky.[16] James Challis started searching for it
in July 1846, and he sighted this planet on September 23, 1846.[17]
3. R. Hermann published claims in 1877 of his discovery of a new element beneath tantalum in
the periodic table, which he named neptunium, after the Greek god of the oceans and
seas.[18][19] However this metal was later recognized to be an alloy of the elements niobium
and tantalum.[20] The name "neptunium" was later given to the synthetic element one step
past uranium in the Periodic Table, which was discovered by nuclear physics researchers in
1940.[21]

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External links
Germanium (http://www.periodicvideos.com/videos/032.htm) at The Periodic Table of Videos
(University of Nottingham)

Retrieved from "https://en.wikipedia.org/w/index.php?title=Germanium&oldid=1263801138"