Germanium 12242 222989643 2008-07-02T01:51:37Z 151.203.62.96 /* Applications */ {{confuse|geranium}} {{Elementbox_header | number=32 | symbol=Ge | name=germanium | left=[[gallium]] | right=[[arsenic]] | above=[[silicon|Si]] | below=[[tin|Sn]] | color1=#cccc99 | color2=black }} {{Elementbox_series | [[metalloid]]s }} {{Elementbox_groupperiodblock | group=14 | period=4 | block=p }} {{Elementbox_appearance_img | Germanium| grayish white }} {{Elementbox_atomicmass_gpm | 72.64[[List of elements by atomic mass|(1)]] }} {{Elementbox_econfig | &#91;[[argon|Ar]]&#93; 3d<sup>10</sup> 4s<sup>2</sup> 4p<sup>2</sup> }} {{Elementbox_epershell | 2, 8, 18, 4 }} {{Elementbox_section_physicalprop | color1=#cccc99 | color2=black }} {{Elementbox_phase | [[solid]] }} {{Elementbox_density_gpcm3nrt | 5.323 }} {{Elementbox_densityliq_gpcm3mp | 5.60 }} {{Elementbox_meltingpoint | k=1211.40 | c=938.25 | f=1720.85 }} {{Elementbox_boilingpoint | k=3106 | c=2833 | f=5131 }} {{Elementbox_heatfusion_kjpmol | 36.94 }} {{Elementbox_heatvaporiz_kjpmol | 334 }} {{Elementbox_heatcapacity_jpmolkat25 | 23.222 }} {{Elementbox_vaporpressure_katpa | 1644 | 1814 | 2023 | 2287 | 2633 | 3104 | comment= }} {{Elementbox_section_atomicprop | color1=#cccc99 | color2=black }} {{Elementbox_crystalstruct | [[Face-centered cubic]] }} {{Elementbox_oxistates | 4, 2,<ref>{{cite web|url=http://www.webelements.com/webelements/compounds/text/Ge/F2Ge1-13940631.html|title=Germanium: germanium(II) chloride compound data|accessdate=2007-12-10|publisher=WebElements.com}}</ref><br />([[amphoteric]] oxide) }} {{Elementbox_electroneg_pauling | 2.01 }} {{Elementbox_ionizationenergies4 | 762 | 1537.5 | 3302.1 }} {{Elementbox_atomicradius_pm | 125 }} {{Elementbox_atomicradiuscalc_pm | 125 }} {{Elementbox_covalentradius_pm | 122 }} {{Elementbox_section_miscellaneous | color1=#cccc99 | color2=black }} {{Elementbox_magnetic | [[Diamagnetic]] }} {{Elementbox_thermalcond_wpmkat300k | 60.2 }} {{Elementbox_thermalexpansion_umpmkat25 | 6.0 }} {{Elementbox_speedofsound_rodmpsat20 | 5400 }} {{Elementbox_mohshardness | 6.0 }} {{Elementbox_cas_number | 7440-56-4 }} {{Elementbox_isotopes_begin | color1=#cccc99 | color2=black }} {{Elementbox_isotopes_decay | mn=68 | sym=Ge | na=[[synthetic radioisotope|syn]] | hl=270.8 [[day|d]] | dm=[[electron capture|ε]] | de=- | pn=68 | ps=[[gallium|Ga]] }} {{Elementbox_isotopes_stable | mn=70 | sym=Ge | na=21.23% | n=38 }} {{Elementbox_isotopes_decay | mn=71 | sym=Ge | na=[[synthetic radioisotope|syn]] | hl=11.26 [[day|d]] | dm=[[electron capture|ε]] | de=- | pn=71 | ps=[[gallium|Ga]] }} {{Elementbox_isotopes_stable | mn=72 | sym=Ge | na=27.66% | n=40 }} {{Elementbox_isotopes_stable | mn=73 | sym=Ge | na=7.73% | n=41 }} {{Elementbox_isotopes_stable | mn=74 | sym=Ge | na=35.94% | n=42 }} {{Elementbox_isotopes_decay | mn=76 | sym=Ge | na=7.44% | hl=1.78&times;10<sup>21</sup> [[year|y]] | dm=[[Double beta decay|β<sup>-</sup>β<sup>-</sup>]] | de=- | pn=76 | ps=[[selenium|Se]] }} {{Elementbox_isotopes_end}} {{Elementbox_footer | color1=#cccc99 | color2=black }} '''Germanium''' ({{pronEng|dʒɚˈmeɪniəm}}) is a [[chemical element]] with the symbol '''Ge''' and [[atomic number]] 32. This lustrous, hard, silver-white [[metalloid]] is chemically similar to [[tin]]. Germanium forms a large number of [[organometallic]] compounds and is an important [[semiconductor]] material used in [[transistor]]s. It is named after the country of [[Germany]]. == Notable characteristics == Germanium is a hard, grayish-white element that has a metallic luster and the same crystal structure as [[diamond]]. Germanium is a [[semiconductor]]. 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>. Along with [[silicon]], [[gallium]], [[bismuth]], [[antimony]], and [[water]], it is one of the few substances that expands as it solidifies (i.e. [[freezing|freezes]]) from its molten state. Germanium releases high energy electrons if bombarded with alpha particles and is used in combination with radon for the nuclear batteries patented by Bruce Perreault. == 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 [[analog (chemistry)|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> <tr> <th>Property</th> <th>Ekasilicon</th> <th>Germanium</th> </tr><tr> <td>atomic mass (amu)</td> <td>72</td> <td>72.64</td> </tr><tr> <td>density (g/cm³)</td> <td>5.5</td> <td>5.35</td> </tr><tr> <td>boiling point (°C)</td> <td>high</td> <td>947</td> </tr><tr> <td>color</td> <td>grey</td> <td>grey</td> </tr> </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. Germanium differs from silicon in that the supply of silicon is only limited by production capacity, while that for germanium is limited by the shortage of exploitable sources. == Applications == One of the leading uses for germanium is as a replacement for silica in the stationary phase in [[chromatography]]. GeO<sub>2</sub> is an isostructural analogue of SiO<sub>2</sub> and is compatible with the silica network present in the silica stationary phase.{{fact|date=February 2008}} <!-- This paragraph also needs to link to WP article(s) that explain what "stationary phase in chromatography" actually means, since most readers won't have a clue about it. --> 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 [[effects pedal]]s by musicians who wish to reproduce the distinctive tonal character of the [[Fuzzbox|"fuzz"-tone]] from the early [[rock and roll]] era, most notably the [[Dallas Arbiter]] [[Fuzz Face]]. Vintage effects pedals known to contain germanium transistors have shown marked increases in collector value for this reason alone. Germanium is a highly important [[infra-red]] optical material and can be readily cut and polished into lenses and windows. It is used particularly as the front optic in thermal imaging cameras working in the 8 to 14 micron wavelength range for passive thermal imaging and for hot-spot detection in military and fire fighting applications. The material has a very high [[refractive index]] (4.0) and so needs to be anti-reflection coated. 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 rough treatment. 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. Other uses: * [[Alloy]]ing agent (see below) * Phosphor in [[fluorescent lamp]]s * High purity germanium single crystal detectors can precisely identify radiation sources, e.g., for airport security * Germanium substrate wafers for high-efficiency multi-junction solar cells for space applications 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. 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. Crystals of high purity germanium are used in [[Germanium detector|detectors]] for [[gamma spectroscopy]] and the search for [[dark matter]]. 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]]). == Value == In 1998 the cost of germanium was about [[United States dollar|US$]]1.70 per [[gram]]. The year-end price for zone-refined germanium had (generally) decreased since then until 2005 when prices began to increase.<ref>{{cite journal | author = | year = 2003 | month = January | title = Germanium | journal = U.S. Geological Survey Mineral Commodity Summaries | volume = | issue = | pages = 2 | id =[http://minerals.usgs.gov/minerals/pubs/commodity/germanium/220303.pdf]}}</ref><ref>{{cite journal | author = | year = 2004 | month = January | title = Germanium | journal = U.S. Geological Survey Mineral Commodity Summaries | volume = | issue = | pages = 2 | id =[http://minerals.usgs.gov/minerals/pubs/commodity/germanium/germamcs04.pdf]}}</ref><ref>{{cite journal | author = | year = 2005 | month = January | title = Germanium | journal = U.S. Geological Survey Mineral Commodity Summaries | volume = | issue = | pages = 2 | id =[http://minerals.usgs.gov/minerals/pubs/commodity/germanium/germamcs05.pdf]}}</ref><ref>{{cite journal | author = | year = 2006 | month = January | title = Germanium | journal = U.S. Geological Survey Mineral Commodity Summaries | volume = | issue = | pages = 2 | id =[http://minerals.usgs.gov/minerals/pubs/commodity/germanium/germamcs06.pdf]}}</ref><ref>{{cite journal | author = | year = 2007 | month = January | title = Germanium | journal = U.S. Geological Survey Mineral Commodity Summaries | volume = | issue = | pages = 2 | id =[http://minerals.usgs.gov/minerals/pubs/commodity/germanium/germamcs07.pdf]}}</ref><ref>{{cite journal | author = Gerald R. Smith | year = 2008 | month = January | title = Mineral Commodity Summaries 2008 | journal = U.S. Geological Survey Mineral Commodity Summaries | volume = | issue = | pages = 202 | id =[http://minerals.usgs.gov/minerals/pubs/commodity/germanium/germamcs07.pdf]}}</ref>: ::1999.....$1,400 per kilogram (or $1.40 per gram) ::2000.....$1,250 per kilogram (or $1.25 per gram) ::2001.....$890 per kilogram (or $0.89 per gram) ::2002.....$620 per kilogram (or $0.62 per gram) ::2003.....$380 per kilogram (or $0.38 per gram) ::2004.....$600 per kilogram (or $0.60 per gram) ::2005.....$660 per kilogram (or $0.66 per gram) ::2006.....$880 per kilogram (or $0.88 per gram) ::2007.....$1240 per kilogram (or $1.24 per gram) ==Compounds== Some [[inorganic]] germanium compounds include [[germane|Germanium tetrahydride]] (GeH<sub>4</sub>), [[germanium tetrachloride]] (GeCl<sub>4</sub>), and [[Germanium dioxide]] (germania) (GeO<sub>2</sub>). The dioxide exhibts the unusual property of having a high refractive index for visible light, but transparent to [[infrared]] light. Some [[Organometallic chemistry|organic]] compounds of germanium include [[tetramethylgermane]] (Ge(CH<sub>3</sub>)<sub>4</sub>) and [[tetraethylgermane]] (Ge(C<sub>2</sub>H<sub>5</sub>)<sub>4</sub>). The 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. Germanium also occurs in the III oxidation state, but only in the Ge<sub>2</sub><sup>6+</sup> cation.<ref>{{cite web|url=http://www.webelements.com/webelements/compounds/text/Ge/Ge2H6-13818898.html|title=Germanium: germanium(III) hydride compound data|accessdate=2007-12-10|publisher=WebElements.com}}</ref> ;See also *[[:Category:Germanium compounds]] *[[Germane]] *[[Germanide]] ==Properties== Pure germanium is known to spontaneously extrude very long [[screw dislocation]]s, 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 end up touching, they may lead to an electrical short. [[FDA]] research has concluded that germanium, when used as a nutritional supplement, "presents potential human health hazard".<ref>{{cite journal | author = Tao, S.H. and Bolger, P.M. | year = 1997 | month = June | title = Hazard Assessment of Germanium Supplements | journal = Regulatory Toxicology and Pharmacology | volume = 25 | issue = 3 | pages = 211–219 | id = | url = http://www.ingentaconnect.com/search/expand?pub=infobike://ap/rt/1997/00000025/00000003/art01098&unc= | doi = 10.1006/rtph.1997.1098 }}</ref> ==References== *[http://periodic.lanl.gov/elements/32.html Los Alamos National Laboratory &ndash; Germanium] <references/> == External links == {{Commons|Germanium}} {{wiktionary|germanium}} *[http://www.webelements.com/webelements/elements/text/Ge/index.html WebElements.com &ndash; Germanium] {{clear}} {{compact periodic table}} [[Category:Chemical elements]] [[Category:Metalloids]] [[Category:Semiconductor materials]] [[Category:Germanium]] [[Category:Optical materials]] [[Category:Infrared sensor materials]] <!-- interwiki --> [[af:Germanium]] [[ar:جرمانيوم]] [[bn:জার্মেনিয়াম]] [[be:Германій]] [[bs:Germanijum]] [[bg:Германий]] [[ca:Germani]] [[cs:Germanium]] [[co:Germaniu]] [[cy:Germaniwm]] [[da:Germanium]] [[de:Germanium]] [[et:Germaanium]] [[el:Γερμάνιο]] [[es:Germanio]] [[eo:Germaniumo]] [[eu:Germanio]] [[fa:ژرمانیوم]] [[fr:Germanium]] [[fur:Gjermani]] [[ga:Gearmáiniam]] [[gv:Germaanium]] [[gl:Xermanio]] [[ko:저마늄]] [[hy:Գերմանիում]] [[hi:जर्मेनियम]] [[hr:Germanij]] [[io:Germanio]] [[id:Germanium]] [[is:German]] [[it:Germanio]] [[he:גרמניום]] [[jv:Germanium]] [[sw:Gerimani]] [[ht:Jèmanyòm]] [[ku:Germanyûm]] [[la:Germanium]] [[lv:Germānijs]] [[lb:Germanium]] [[lt:Germanis]] [[jbo:dotyjinme]] [[hu:Germánium]] [[ms:Germanium]] [[nl:Germanium]] [[ja:ゲルマニウム]] [[no:Germanium]] [[nn:Germanium]] [[oc:Germani]] [[uz:Germaniy]] [[nds:Germanium]] [[pl:German]] [[pt:Germânio]] [[ro:Germaniu]] [[qu:Germanyu]] [[ru:Германий]] [[scn:Girmaniu]] [[simple:Germanium]] [[sk:Germánium]] [[sl:Germanij]] [[sr:Германијум]] [[sh:Germanijum]] [[fi:Germanium]] [[sv:Germanium]] [[ta:ஜேர்மானியம்]] [[th:เจอร์เมเนียม]] [[vi:Gecmani]] [[tr:Germanyum]] [[uk:Германій]] [[ur:جرمانیئم]] [[zh:锗]]