Difference between revisions of "Germanium" - New World Encyclopedia

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{{Elementbox_header | number=32 | symbol=Ge | name=germanium | left=[[gallium]] | right=[[arsenic]] | above=[[silicon|Si]] | below=[[tin|Sn]] | color1=#cccc99 | color2=black }}
 
{{Elementbox_header | number=32 | symbol=Ge | name=germanium | left=[[gallium]] | right=[[arsenic]] | above=[[silicon|Si]] | below=[[tin|Sn]] | color1=#cccc99 | color2=black }}
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'''Germanium''' ([[International Phonetic Alphabet|IPA]]: {{IPA|/dʒə(r)ˈmeɪniəm/}}) is a [[chemical element]] in the [[periodic table]] that has the symbol '''Ge''' and [[atomic number]] 32. This is a lustrous, hard, silver-white [[metalloid]] that is chemically similar to [[tin]]. Germanium forms a large number of [[organometallic]] compounds and is an important [[semiconductor]] material used in [[transistor]]s.
+
'''Germanium''' (chemical symbol '''Ge''', [[atomic number]] 32) is a lustrous, hard, grayish-white [[chemical element]]. It is classified as a [[metalloid]]—that is, its chemical properties are intermediate between those of [[metal]]s and [[nonmetal]]s. It is a valuable [[semiconductor]] material.
 +
{{toc}}
 +
The development of the germanium transistor opened the door to numerous applications in [[solid state (electronics)|solid-state]] electronics. Currently, germanium and its compounds are mainly used for [[fiber-optic]] communications networks and [[infrared]] [[night vision]] systems. In addition, germanium is a catalyst for certain polymerization reactions, and single-crystal detectors made with highly purified germanium can be used to identify sources of radiation. Germanium dioxide is useful for wide-angle [[camera]] lenses and [[microscope]] objective lenses, and silicon germanide is becoming an important semiconductor for high-speed [[integrated circuit]]s.
  
−
== Occurrence ==
+
== Occurrence and extraction ==
−
This element is found in [[argyrodite]] ([[sulfide]] of germanium and [[silver]]); [[coal]]; [[germanite]]; [[zinc]] ores; and other [[mineral]]s.
 
−
See also ''[[:Category:Germanium minerals]]''
 
  
−
Germanium is obtained commercially from zinc ore processing smelter dust and from the [[combustion]] by-products of certain coals. A large reserve of this element is therefore in coal sources.
+
Germanium ([[Latin]] ''Germania'', for [[Germany]]) is found in [[argyrodite]] ([[sulfide]] of germanium and [[silver]]), [[coal]], [[germanite]], [[zinc]] ores, and other [[mineral]]s.
  
−
This metalloid can be extracted from other metals by fractional [[distillation]] of its volatile tetrachloride. This technique permits the production of ultra-high purity germanium.
+
Germanium is obtained commercially from the smelter dust of zinc ore processing and the [[combustion]] byproducts of certain coals. A large reserve of this element is found in coal sources.
 +
 
 +
This metalloid can be extracted from associated metals by fractional [[distillation]] of its volatile tetrachloride. This technique permits the production of ultra-high-purity germanium.
  
 
== History ==
 
== History ==
−
In [[1871]] germanium ([[Latin]] ''Germania'' for [[Germany]]) was one of the elements that [[Dmitri Mendeleev]] [[Mendeleev's predicted elements|predicted to exist]] as a missing analogue of the [[silicon]] group (Mendeleev called it "[[Mendeleev's predicted elements#Ekasilicon and Germanium|ekasilicon]]"). The existence of this element was proven by [[Clemens Winkler]] in [[1886]]. This discovery was an important confirmation of Mendeleev's idea of element periodicity.
 
  
−
<table>
+
[[Dmitri Mendeleev]] predicted the existence of germanium (as well as other unidentified elements) in 1871. Thinking of it as a missing member of the [[silicon]] group, he called it ''ekasilicon''. When the element was discovered by [[Clemens Winkler]] in 1886, it served as an important confirmation of Mendeleev's idea of element periodicity.
−
<tr>
+
 
−
<th>Property</th>
+
{| border=2 cellpadding=6
−
<th>Ekasilicon</th>
+
| '''Property'''
−
<th>Germanium</th>
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| '''Ekasilicon'''
−
</tr><tr>
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| '''Germanium'''
−
<td>atomic mass</td>
+
|-
−
<td>72</td>
+
| atomic mass
−
<td>72.59</td>
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| 72
−
</tr><tr>
+
| 72.59
−
<td>density (g/cm³)</td>
+
|-
−
<td>5.5</td>
+
| density
−
<td>5.35</td>
+
| 5.5
−
</tr><tr>
+
| 5.35
−
<td>melting point (°C)</td>
+
|-
−
<td>high</td>
+
|melting point (°C)
−
<td>947</td>
+
| high
−
</tr><tr>
+
| 947
−
<td>color</td>
+
|-
−
<td>gray</td>
+
|color
−
<td>gray</td>
+
| gray
−
</tr>
+
| gray
−
</table>
+
|-
−
The development of the germanium transistor opened the door to countless applications of [[solid state (electronics)|solid state]] electronics. From [[1950]] through the early [[1970s]], this area provided an increasing market for germanium, but then high purity silicon began replacing germanium in transistors, [[diode]]s, and rectifiers. Silicon has superior electrical properties, but requires much higher purity samples&mdash;a purity which could not be commercially achieved in the early days. Meanwhile, demand for germanium in [[fiber optics]] communication networks, infrared [[night vision]] systems, and polymerization catalysts increased dramatically.  These end uses represented 85% of worldwide germanium consumption for [[2000]].
+
|}
 +
 
 +
The development of the germanium transistor opened the door to countless applications in [[solid state (electronics)|solid state]] electronics. From 1950 through the early 1970s, this area provided an increasing market for germanium, but then high-purity silicon began replacing germanium in transistors, [[diode]]s, and rectifiers. Silicon has superior electrical properties but requires much higher purity samples&mdash;a purity that could not be commercially achieved in the early days. Meanwhile, the demand for germanium increased dramatically for other applications&mdash;[[fiber optics]] communication networks, [[infrared]] [[night vision]] systems, and polymerization catalysts.
  
 
== Notable characteristics ==
 
== Notable characteristics ==
  
−
Germanium is a hard, grayish-white element that has a metallic luster and the same crystal structure as [[diamond]]. In addition, it is important to note that germanium is a semiconductor, with electrical properties between those of a [[metal]] and an [[insulator]]. In its pure state, this metalloid is [[crystal]]line, brittle and retains its [[Lustre (mineralogy)|lustre]] in air at room temperature. [[Zone refining]] techniques have led to the production of crystalline germanium for [[semiconductor]]s that have an impurity of only one part in 10<sup>10</sup>.
+
In the [[periodic table]], germanium is located in group 14 (former group 4A), between [[silicon]] and [[tin]], and in period 4, between [[gallium]] and [[arsenic]]. Like silicon and arsenic, it is a [[metalloid]].
 +
 
 +
[[Image:GermaniumUSGOV.jpg|thumb|left|A germanium bowl]]
 +
 
 +
In its pure state, germanium is [[crystal]]line and brittle, and it retains its luster in air at room temperature. In terms of its atomic arrangement, it has the same crystal structure as [[diamond]].
 +
 
 +
Germanium is a semiconductor, with electrical properties between those of a [[metal]] and an [[insulator]]. Unlike most semiconductors, it has a narrow [[band gap]], allowing it to respond efficiently to [[infrared]] light. [[Zone refining]] techniques have enabled the production of extremely pure, crystalline germanium for [[semiconductor]]s (with an impurity level of only one part in 10<sup>10</sup>).
 +
 
 +
=== Isotopes ===
 +
 
 +
The [[isotope]]s of germanium range in atomic mass number from 58 to 89. Of these, there are four stable isotopes: <sup>70</sup>Ge, <sup>72</sup>Ge, <sup>73</sup>Ge, and <sup>74</sup>Ge. In addition, <sup>76</sup>Ge has been found to have an extremely long half-life, so that for all practical purposes it may be considered stable. The other radioisotopes are very short-lived.
 +
 
 +
==Compounds==
 +
 
 +
* '''Germane''' (or '''germanium tetrahydride''', GeH<sub>4</sub>): It is the simplest germanium hydride and one of the most useful compounds of germanium. It is a gas at ordinary temperatures and pressures. Its molecules have a [[tetrahedral]] shape, similar to the molecules of silane (SiH<sub>4</sub>) and methane (CH<sub>4</sub>). It is flammable and, when burned in air, produces germanium dioxide (GeO<sub>2</sub>) and [[water]]. The gas decomposes at a temperature of about 600K, yielding germanium and hydrogen. For this reason, the [[semiconductor]] industry uses germane as a starting material for growing germanium [[crystal]]s, using an approach called ''epitaxy'' (the growth of a crystal on a crystalline substrate).<ref>Venkatasubramanian, R., R. T. Pickett, and M. L. Timmons. “Epitaxy of germanium using germane in the presence of tetramethylgermanium.” ''Journal of Applied Physics'' 66 (1989): 5662-5664. {{doi|10.1063/1.343633}}</ref>
 +
 
 +
* '''Germanium dioxide''' (or '''germanium oxide''' or '''germania''', GeO<sub>2</sub>): This compound may come in the form of a white powder or colorless crystals, with a melting point of 1,115 °C. It is a structural analog of [[silicon dioxide]] (silica). It forms a “[[passivation layer]]” (protective surface film) on pure germanium that is in contact with atmospheric oxygen. The high [[refractive index]] and low optical dispersion of this oxide make it useful for wide-angle camera [[lens]]es and [[optical microscope]] lenses. A mixture of silicon dioxide and germanium dioxide ("silica-germania") is used for [[optical fiber]]s and [[optical waveguide]]s. As GeO<sub>2</sub> is transparent in the [[infrared]] region, it is useful for manufacturing infrared windows and lenses, for night-vision technology in the military and luxury vehicles.<ref name=CRC>Hammond, C. R. "The Elements" in David R. Lide (ed.), ''CRC Handbook of Chemistry and Physics'', 85th Edition. Boca Raton, FL: CRC Press, 2004. ISBN 0849304857</ref>
 +
 
 +
* '''Germanium tetrachloride''' (GeCl<sub>4</sub>): This colorless liquid is used as an intermediate in the production of purified germanium metal. In recent years, it is being used almost exclusively as an intermediate for the production of GeO<sub>2</sub>, an oxide glass with several unique properties and applications, noted above.
 +
 
 +
* '''Organogermanium compounds''': These are [[Organic chemistry|organic compound]]s in which germanium atoms are directly bound to [[carbon]] atoms.<ref>Yamamoto, Hisashi and Koichiro Oshima (eds.). ''Main Group Metals in Organic Synthesis''. Hoboken, NJ: John Wiley & Sons, 2004. ISBN 3527305084</ref>. Examples are tetramethyl germanium and tetraethyl germanium. The chemistry of these compounds lies between that of organosilicon and organotin compounds. Organogermanium compounds are advocated as nontoxic alternatives to many toxic organotin reagents. Compounds such as tetramethyl germanium and tetraethyl germanium are used in the microelectronics industry as precursors for germanium oxide [[chemical vapor deposition]] processes.
  
 
== Applications ==
 
== Applications ==
−
Unlike most semiconductors, germanium has a small [[band gap]], allowing it to efficiently respond to [[infrared]] light. It is therefore used in infrared [[spectroscope]]s and other optical equipment which require extremely sensitive infrared detectors. Its oxide's [[refractive index|index of refraction]] and dispersion properties make germanium useful in wide-angle [[camera]] lenses and in [[microscope]] objective lenses.
 
  
−
Germanium transistors are still used in some [[Stompbox|stompboxes]] by musicians who wish to reproduce the distinctive tonal character of the [[Fuzzbox|"fuzz"-tone]] from the early [[rock and roll]] era. Vintage [[Stompbox|stompboxes]] known to contain germanium transistors have shown marked increases in collector value for this reason alone.
+
* As germanium responds efficiently to [[infrared]] light, it is useful for infrared [[spectroscopy|spectroscope]]s and other optical equipment requiring highly sensitive infrared detectors.
 +
 
 +
* The [[refractive index|index of refraction]] and dispersion properties of germanium oxide make it useful in wide-angle [[camera]] lenses and [[microscope]] objective lenses.
 +
 
 +
* Silicon germanide (or "silicon-germanium," SiGe) is rapidly becoming an important semiconductor material for use in high-speed [[integrated circuit]]s.
 +
 
 +
* Germanium may be used as a phosphor in [[fluorescent lamp]]s.
 +
 
 +
* It is a catalyst for certain polymerization reactions.
 +
 
 +
* Single-crystal detectors made with high-purity germanium can precisely identify sources of radiation. These devices can be useful for airport security.
  
−
The alloy Silicon germanide (commonly referred to as "silicon-germanium", or [[SiGe]]) is rapidly becoming an important semiconductor material, for use in high speed integrated circuits. Circuits utilising the properties of Si-SiGe junctions can be much faster than those using silicon alone.
+
* Some compounds of germanium are useful as chemotherapeutic agents, because they are toxic for certain [[bacterium|bacteria]] but have low toxicity toward [[mammal]]s.
−
[[Image:GermaniumUSGOV.jpg|thumb|Germanium bowl]]
 
−
Other uses:
 
−
* [[Alloy]]ing agent (see below)
 
−
* Phosphor in [[fluorescent lamp]]s
 
−
* [[catalyst]]
 
−
* High purity germanium single crystal detectors can precisely identify radiation sources (e.g. for airport security)
 
  
−
Certain compounds of germanium have low toxicity to [[mammal]]s, but have toxic effects against certain [[bacterium|bacteria]]. This property makes these compounds useful as chemotherapeutic agents.
+
* Vintage acoustic [[Stompbox|stompboxes]] containing germanium transistors have markedly increased in collector value for their distinctive tonal quality.
  
−
Germanium is useful for [[single crystal]] [[neutron scattering|neutron]] or [[Synchrotron light|synchrotron X-ray]] [[Crystal monochromator|monochromator]] for [[beamline]]s. The reflectivity has advantages over silicon in neutron and [[High energy X-rays|High energy X-ray]] applications.
+
* In recent years, germanium is being increasingly used in precious metal alloys. For instance, in sterling [[silver]] (an alloy of silver with copper or other metals), the presence of germanium has been found to increase tarnish resistance and reduce [[firescale]] (a red or purple stain that appears).
  
−
While germanium has been claimed as an attractive nutritional supply, able to cure even cancer and [[AIDS]], [[FDA]] research has concluded that the offered supplements "present potential human health hazard".<ref>{{cite journal
+
== Precaution ==
−
  | author = Tao, S.H. and Bolger, P.M.
+
 
 +
Germanium has been called an attractive nutritional supplement, able to cure diseases such as [[cancer]] and [[AIDS]]. As noted above, some germanium compounds are toxic for bacteria but have low toxicity toward mammals. Yet, a 1997 study sponsored by the U.S. Food and Drug Administration concluded that nutritional supplements containing germanium "present potential human health hazard."<ref>{{cite journal
 +
  | author = Tao, S. H. and Bolger, P. M.
 
  | year = 1997
 
  | year = 1997
 
  | month = June
 
  | month = June
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  }}</ref>
 
  }}</ref>
  
−
In recent years germanium has seen increasing use in precious metal alloys.  In [[sterling silver]] alloys, for instance, it has been found to reduce [[firescale]], increase tarnish resistance, and increase the alloy's response to precipitation hardening (see [[Argentium sterling silver]]).
+
== See also ==
−
 
 
−
==Compounds==
 
−
 
 
−
Some [[inorganic]] germanium compounds include [[Germane]] or [[Germanium tetrahydride]] (GeH<sub>4</sub>), [[Germanium tetrachloride]] (GeCl<sub>4</sub>),
 
−
and [[Germanium dioxide]] (germania) (GeO<sub>2</sub>). Some [[organic]] compounds of germanium include tetramethylgermane or tetramethyl germanium, (Ge(CH<sub>3</sub>)<sub>4</sub>), and tetraethylgermane or tetraethyl germanium, (Ge(C<sub>2</sub>H<sub>5</sub>)<sub>4</sub>). Recently a new organogermanium compound [[isobutylgermane]] ((CH<sub>3</sub>)<sub>2</sub>CHCH<sub>2</sub>GeH<sub>3</sub>), was reported as the less hazardous liquid substitute for toxic [[germane]] gas in [[semiconductor]] applications. (Reference: Presentation at ACCGE conference, held at Big Sky Resort in Montana, USA, July 2005).
 
  
−
== See also==
 
 
* [[Chemical element]]
 
* [[Chemical element]]
−
* [[Metal]]
+
* [[Metalloid]]
 
* [[Periodic table]]
 
* [[Periodic table]]
  
−
==Footnotes==
+
==Notes==
 
<references/>
 
<references/>
  
 
==References==
 
==References==
−
*[http://periodic.lanl.gov/elements/32.html Los Alamos National Laboratory &ndash; Germanium]
+
* Hammond, C. R. "The Elements" in David R. Lide (ed.), ''CRC Handbook of Chemistry and Physics'', 85th ed. Boca Raton, FL: CRC Press, 2004. ISBN 0849304857
 +
* Yamamoto, Hisashi and Koichiro Oshima (eds.). ''Main Group Metals in Organic Synthesis''. Hoboken, NJ: John Wiley & Sons, 2004. ISBN 3527305084
  
 
== External links ==
 
== External links ==
−
 
+
All links retrieved June 20 2017.
 
*[http://www.webelements.com/webelements/elements/text/Ge/index.html WebElements.com &ndash; Germanium]
 
*[http://www.webelements.com/webelements/elements/text/Ge/index.html WebElements.com &ndash; Germanium]
  
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[[Category:Chemical elements]]
 
[[Category:Chemical elements]]
  
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{{credit|83577545}}
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{{credit5|Germanium|83577545|Germane|82763596|Germanium_dioxide|77868756|Germanium_tetrachloride|77678330|Organogermanium_compound|84564671}}

Latest revision as of 09:43, 5 December 2022


32 gallium ← germanium → arsenic
Si
↑
Ge
↓
Sn
Ge-TableImage.png
periodic table
General
Name, Symbol, Number germanium, Ge, 32
Chemical series metalloids
Group, Period, Block 14, 4, p
Appearance grayish white
Germanium.jpg
Atomic mass 72.64(1) g/mol
Electron configuration [Ar] 3d10 4s2 4p2
Electrons per shell 2, 8, 18, 4
Physical properties
Phase solid
Density (near r.t.) 5.323 g/cm³
Liquid density at m.p. 5.60 g/cm³
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
Heat capacity (25 °C) 23.222 J/(mol·K)
Vapor pressure
P/Pa 1 10 100 1 k 10 k 100 k
at T/K 1644 1814 2023 2287 2633 3104
Atomic properties
Crystal structure Face-centered cubic
Oxidation states 4
(amphoteric oxide)
Electronegativity 2.01 (Pauling scale)
Ionization energies
(more) 		1st: 762 kJ/mol
2nd: 1537.5 kJ/mol
3rd: 3302.1 kJ/mol
Atomic radius 125 pm
Atomic radius (calc.) 125 pm
Covalent radius 122 pm
Miscellaneous
Magnetic ordering no data
Thermal conductivity (300 K) 60.2 W/(m·K)
Thermal expansion (25 °C) 6.0 µm/(m·K)
Speed of sound (thin rod) (20 °C) 5400 m/s
Mohs hardness 6.0
CAS registry number 7440-56-4
Notable isotopes
Main article: Isotopes of germanium
iso NA half-life DM DE (MeV) DP
68Ge syn 270.8 d ε - 68Ga
70Ge 21.23% Ge is stable with 38 neutrons
71Ge syn 11.26 d ε - 71Ga
72Ge 27.66% Ge is stable with 40 neutrons
73Ge 7.73% Ge is stable with 41 neutrons
74Ge 35.94% Ge is stable with 42 neutrons
76Ge 7.44% Ge is stable with 44 neutrons

Germanium (chemical symbol Ge, atomic number 32) is a lustrous, hard, grayish-white chemical element. It is classified as a metalloid—that is, its chemical properties are intermediate between those of metals and nonmetals. It is a valuable semiconductor material.

The development of the germanium transistor opened the door to numerous applications in solid-state electronics. Currently, germanium and its compounds are mainly used for fiber-optic communications networks and infrared night vision systems. In addition, germanium is a catalyst for certain polymerization reactions, and single-crystal detectors made with highly purified germanium can be used to identify sources of radiation. Germanium dioxide is useful for wide-angle camera lenses and microscope objective lenses, and silicon germanide is becoming an important semiconductor for high-speed integrated circuits.

Occurrence and extraction

Germanium (Latin Germania, for Germany) is found in argyrodite (sulfide of germanium and silver), coal, germanite, zinc ores, and other minerals.

Germanium is obtained commercially from the smelter dust of zinc ore processing and the combustion byproducts of certain coals. A large reserve of this element is found in coal sources.

This metalloid can be extracted from associated metals by fractional distillation of its volatile tetrachloride. This technique permits the production of ultra-high-purity germanium.

History

Dmitri Mendeleev predicted the existence of germanium (as well as other unidentified elements) in 1871. Thinking of it as a missing member of the silicon group, he called it ekasilicon. When the element was discovered by Clemens Winkler in 1886, it served as an important confirmation of Mendeleev's idea of element periodicity.

Property Ekasilicon Germanium
atomic mass 72 72.59
density 5.5 5.35
melting point (°C) high 947
color gray gray

The development of the germanium transistor opened the door to countless applications in solid state electronics. 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. Silicon has superior electrical properties but requires much higher purity samples—a purity that could not be commercially achieved in the early days. Meanwhile, the demand for germanium increased dramatically for other applications—fiber optics communication networks, infrared night vision systems, and polymerization catalysts.

Notable characteristics

In the periodic table, germanium is located in group 14 (former group 4A), between silicon and tin, and in period 4, between gallium and arsenic. Like silicon and arsenic, it is a metalloid.

A germanium bowl

In its pure state, germanium is crystalline and brittle, and it retains its luster in air at room temperature. In terms of its atomic arrangement, it has the same crystal structure as diamond.

Germanium is a semiconductor, with electrical properties between those of a metal and an insulator. Unlike most semiconductors, it has a narrow band gap, allowing it to respond efficiently to infrared light. Zone refining techniques have enabled the production of extremely pure, crystalline germanium for semiconductors (with an impurity level of only one part in 1010).

Isotopes

The isotopes of germanium range in atomic mass number from 58 to 89. Of these, there are four stable isotopes: 70Ge, 72Ge, 73Ge, and 74Ge. In addition, 76Ge has been found to have an extremely long half-life, so that for all practical purposes it may be considered stable. The other radioisotopes are very short-lived.

Compounds

  • Germane (or germanium tetrahydride, GeH4): It is the simplest germanium hydride and one of the most useful compounds of germanium. It is a gas at ordinary temperatures and pressures. Its molecules have a tetrahedral shape, similar to the molecules of silane (SiH4) and methane (CH4). It is flammable and, when burned in air, produces germanium dioxide (GeO2) and water. The gas decomposes at a temperature of about 600K, yielding germanium and hydrogen. For this reason, the semiconductor industry uses germane as a starting material for growing germanium crystals, using an approach called epitaxy (the growth of a crystal on a crystalline substrate).[1]
  • Germanium dioxide (or germanium oxide or germania, GeO2): This compound may come in the form of a white powder or colorless crystals, with a melting point of 1,115 °C. It is a structural analog of silicon dioxide (silica). It forms a “passivation layer” (protective surface film) on pure germanium that is in contact with atmospheric oxygen. The high refractive index and low optical dispersion of this oxide make it useful for wide-angle camera lenses and optical microscope lenses. A mixture of silicon dioxide and germanium dioxide ("silica-germania") is used for optical fibers and optical waveguides. As GeO2 is transparent in the infrared region, it is useful for manufacturing infrared windows and lenses, for night-vision technology in the military and luxury vehicles.[2]
  • Germanium tetrachloride (GeCl4): This colorless liquid is used as an intermediate in the production of purified germanium metal. In recent years, it is being used almost exclusively as an intermediate for the production of GeO2, an oxide glass with several unique properties and applications, noted above.
  • Organogermanium compounds: These are organic compounds in which germanium atoms are directly bound to carbon atoms.[3]. Examples are tetramethyl germanium and tetraethyl germanium. The chemistry of these compounds lies between that of organosilicon and organotin compounds. Organogermanium compounds are advocated as nontoxic alternatives to many toxic organotin reagents. Compounds such as tetramethyl germanium and tetraethyl germanium are used in the microelectronics industry as precursors for germanium oxide chemical vapor deposition processes.

Applications

  • As germanium responds efficiently to infrared light, it is useful for infrared spectroscopes and other optical equipment requiring highly sensitive infrared detectors.
  • Silicon germanide (or "silicon-germanium," SiGe) is rapidly becoming an important semiconductor material for use in high-speed integrated circuits.
  • It is a catalyst for certain polymerization reactions.
  • Single-crystal detectors made with high-purity germanium can precisely identify sources of radiation. These devices can be useful for airport security.
  • Some compounds of germanium are useful as chemotherapeutic agents, because they are toxic for certain bacteria but have low toxicity toward mammals.
  • Vintage acoustic stompboxes containing germanium transistors have markedly increased in collector value for their distinctive tonal quality.
  • In recent years, germanium is being increasingly used in precious metal alloys. For instance, in sterling silver (an alloy of silver with copper or other metals), the presence of germanium has been found to increase tarnish resistance and reduce firescale (a red or purple stain that appears).

Precaution

Germanium has been called an attractive nutritional supplement, able to cure diseases such as cancer and AIDS. As noted above, some germanium compounds are toxic for bacteria but have low toxicity toward mammals. Yet, a 1997 study sponsored by the U.S. Food and Drug Administration concluded that nutritional supplements containing germanium "present potential human health hazard."[4]

See also

Notes

  1. ↑ Venkatasubramanian, R., R. T. Pickett, and M. L. Timmons. “Epitaxy of germanium using germane in the presence of tetramethylgermanium.” Journal of Applied Physics 66 (1989): 5662-5664. Digital object identifier (DOI): 10.1063/1.343633
  2. ↑ Hammond, C. R. "The Elements" in David R. Lide (ed.), CRC Handbook of Chemistry and Physics, 85th Edition. Boca Raton, FL: CRC Press, 2004. ISBN 0849304857
  3. ↑ Yamamoto, Hisashi and Koichiro Oshima (eds.). Main Group Metals in Organic Synthesis. Hoboken, NJ: John Wiley & Sons, 2004. ISBN 3527305084
  4. ↑ Tao, S. H. and Bolger, P. M. (June 1997). Hazard Assessment of Germanium Supplements. Regulatory Toxicology and Pharmacology 25 (3): 211-219.

References
ISBN links support NWE through referral fees

  • Hammond, C. R. "The Elements" in David R. Lide (ed.), CRC Handbook of Chemistry and Physics, 85th ed. Boca Raton, FL: CRC Press, 2004. ISBN 0849304857
  • Yamamoto, Hisashi and Koichiro Oshima (eds.). Main Group Metals in Organic Synthesis. Hoboken, NJ: John Wiley & Sons, 2004. ISBN 3527305084

External links

All links retrieved June 20 2017.

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