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{{Infokutija Hemijski element
| Hemijski element = Germanij
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'''Germanij''' ([[latinski jezik|lat.]] ''germanium'') jeste [[hemijski element]] sa simbolom '''Ge''' i atomskim brojem 32. On je sjajni, tvrdi, sivo-bijeli [[Polumetali|polumetal]] iz grupe ugljika, hemijski sličan svojim komšijama iz [[14. grupa hemijskih elemenata|IV glavne grupe]] [[periodni sistem elemenata|periodnog sistema elemenata]] [[kalaj]]
Pošto postoji vrlo mali broj [[minerali|minerala]] koji ga sadrže u visokim koncentracijama, germanij je otkriven relativno kasno u historiji hemije. Među elementima po rasprostranjenosti u Zemljinoj kori, on se nalazi približno na 50. mjestu. Ruski [[hemičar]] [[Dmitrij Ivanovič Mendeljejev|Dmitrij Mendeljejev]] je 1869. godine predvidio njegovo postojanje i neke od njegovih osobina na osnovu mjesta u periodnom sistemu kojeg je Mendeljejev kreirao. Dao mi je ''ekasilicij''. Gotovo dva desetljeća kasnije, 1886. godine, [[Clemens Winkler]] je otkrio novi element, kao pratioca srebra i sumpora u rijetkom mineralu nazvanom [[argirodit]]. Mada je novi element izgledom na neki način imao sličnosti sa [[arsen]]om i [[antimon]]om, njegovi kombinirani odnosi u spojevima novog elementa su bili u saglasnosti sa Mendeljejevijim predviđanjima u odnosu na silicij. Winkler je novom elementu dao ime po imenu svoje domovine, [[Njemačka|Njemačke]]. Danas se germanij uglavnom izdvaja iz [[sfalerit]]a (osnovne rude cinka), mada se često industrijski izdvaja i iz ruda srebra, olova i bakra.
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=== Hemijske ===
Elementarni germanij vrlo sporo oksidira do [[germanij dioksid|GeO<sub>2</sub>]] pri 250 °C.<ref name="krxps" /> Germanij ne otapaju razrijeđene kiseline i baze, ali se sporo otapa u koncentriranoj [[sumporna kiselina|sumpornoj kiselini]] a burno reagira sa istopljenim [[baza (hemija)|bazama]] dajući germanate ({{chem|[GeO|3|]|2−}}). Germanij se javlja uglavnom u [[oksidacijsko stanje|oksidacijskom stanju]] +4, mada je poznat veliki broj njegovih spojeva sa oksidacijskim brojem +2.<ref name="greenwood"/> Druga oksidacijska stanja su rijetka, poput +3 koje je dokazano u spoju kao što je Ge<sub>2</sub>Cl<sub>6</sub>, a stanja +3 i +1 su pronađena na površinama oksida,<ref name="xpsstudy" /> ili negativna oksidacijska stanja u germanatim, kao što je -4 u {{chem|GeH|4}}. Klaster anioni germanija ([[Zintl faza|Zintl]] ioni) poput Ge<sub>4</sub><sup>2−</sup>, Ge<sub>9</sub><sup>4−</sup>, Ge<sub>9</sub><sup>2−</sup>, [(Ge<sub>9</sub>)<sub>2</sub>]<sup>6−</sup> su dobijeni izdvajanjem iz [[legura]] koje sadrže alkalne metale i germanij u tečnom amoniju u prisustvu [[etilendiamin]]a ili [[kriptand]]a.<ref name = "greenwood"/><ref name="Coupling" /> Oksidacijska stanja elementa u ovim ionima nisu jednaka cijelom broju, slično kao kod spojeva [[ozon]]a O<sub>3</sub><sup>−</sup>.
Poznata su dva oksida germanija: [[germanij dioksid]] ({{chem|GeO|2}}, ''germanija'') i [[germanij monoksid]], ({{chem|GeO}}).<ref name="HollemanAF" /> Dioksid, GeO<sub>2</sub> se može dobiti žarenjem [[germanij disulfid]]a ({{chem|GeS|2}}). Dioksid je bijeli prah koji se vrlo slabo rastvorljiv u vodi ali reagira sa alkalijama dajući germanate.<ref name="HollemanAF"/> Germanij monoksid se može dobiti reakcijom GeO<sub>2</sub> sa metalnim Ge pri visokim temperaturama.<ref name="HollemanAF"/> Dioksid (i slični oksidi i germanati) pokazuje neobične osobine kao što je neuobičajeno visok [[Indeks prelamanja|indeks prelamanja]] u vidljivom dijelu svjetlosnog spektra, ali je providan u infracrvenom spektru.<ref name="Aggarwal" /><ref name="drugoveiko" /> [[Bizmut germanat]], Bi<sub>4</sub>Ge<sub>3</sub>O<sub>12</sub>, (BGO) se koristi kao [[scintilator]].<ref name="BGO" />
Binarni spojevi sa drugim halkogenim elementima su također poznati, kao što je disulfid ({{chem|GeS|2}}), diselenid ({{chem|GeSe|2}}), monosulfid (GeS), selenid (GeSe) i telurid (GeTe).<ref name = "greenwood"/> GeS<sub>2</sub> se izdvaja kao bijeli talog kada se [[Vodik sulfid|vodik sulfid]] propusti kroz jako kiseli rastvor koji sadrži Ge(IV).<ref name = "greenwood"/>
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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.<ref>{{cite journal|first =Otto H.|last = Johnson|title = Germanium and its Inorganic Compounds|journal = Chem. Rev.|year = 1952|volume= 3|issue =3| page=431|doi = 10.1021/cr60160a002}}</ref> 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.<ref name="HollemanAF"/> Upon melting with [[alkali metal compound|alkaline carbonates]] and [[sulfur]], germanium compounds form salts known as thiogermanates.<ref>{{cite journal|doi=10.1039/a703634e|title=First synthesis of mesostructured thiogermanates|year=1997|last = Fröba|first = Michael |journal=Chemical Communications|issue=18|page=1729|last2=Oberender|first2=Nadine}}</ref>
[[Datoteka:Germane-2D-dimensions.png|lijevo|thumb|German je sličan [[metan]]u.]]
Four tetra[[halides]] are known. Under normal conditions GeI<sub>4</sub> is a solid, GeF<sub>4</sub> a gas and the others volatile liquids. For example, [[germanium tetrachloride]], GeCl<sub>4</sub>, is obtained as a colorless fuming liquid boiling at 83.1 °C by heating the metal with chlorine.<ref name="HollemanAF"/> All the tetrahalides are readily hydrolyzed to hydrated germanium dioxide.<ref name="HollemanAF"/> GeCl<sub>4</sub> is used in the production of organogermanium compounds.<ref name = "greenwood"/> All four dihalides are known and in contrast to the tetrahalides are polymeric solids.<ref name = "greenwood"/> Additionally Ge<sub>2</sub>Cl<sub>6</sub> and some higher compounds of formula Ge<sub>''n''</sub>Cl<sub>2''n''+2</sub> are known.<ref name="HollemanAF"/> The unusual compound Ge<sub>6</sub>Cl<sub>16</sub> has been prepared that contains the Ge<sub>5</sub>Cl<sub>12</sub> unit with a [[neopentane]] structure.<ref name="Raman" />
[[Germane]] (GeH<sub>4</sub>) is a compound similar in structure to [[methane]]. Polygermanes—compounds that are similar to [[alkane]]s—with formula Ge<sub>''n''</sub>H<sub>2''n''+2</sub> containing up to five germanium atoms are known.<ref name = "greenwood"/> The germanes are less volatile and less reactive than their corresponding silicon analogues.<ref name = "greenwood"/> GeH<sub>4</sub> reacts with alkali metals in liquid ammonia to form white crystalline MGeH<sub>3</sub> which contain the GeH<sub>3</sub><sup>−</sup> [[anion]].<ref name = "greenwood"/> The germanium hydrohalides with one, two and three halogen atoms are colorless reactive liquids.<ref name = "greenwood"/>
[[Datoteka:NucleophilicAdditionWithOrganogermanium.png|lijevo|thumb|Nukleofilna adicija sa organogermanijskim spojem.]]
The first [[organogermanium compound]] was synthesized by Winkler in 1887; the reaction of germanium tetrachloride with [[diethylzinc]] yielded [[tetraethylgermane]] ({{chem|Ge(C|2|H|5|)|4}}).<ref name="Winkle2" /> Organogermanes of the type R<sub>4</sub>Ge (where R is an [[alkyl]]) such as [[tetramethylgermane]] ({{chem|Ge(CH|3|)|4}}) and tetraethylgermane are accessed through the cheapest available germanium precursor [[germanium tetrachloride]] and alkyl nucleophiles. Organic germanium hydrides such as [[isobutylgermane]] ({{chem|(CH|3|)|2|CHCH|2|GeH|3}}) were found to be less hazardous and may be used as a liquid substitute for toxic [[germane]] gas in [[semiconductor]] applications. Many germanium [[reactive intermediate]]s are known: [[-yl|germyl]] [[free radical]]s, germylenes (similar to [[carbene]]s), and germynes (similar to [[carbyne]]s).<ref>{{cite journal|title = Reactive intermediates in organogermanium chemistry|first = Jacques|last = Satge|journal = Pure & Appl. Chem.|volume = 56|issue = 1|pages = 137–150|year =1984|doi = 10.1351/pac198456010137}}</ref><ref>{{cite journal|title = Organogermanium Chemistry| first = Denis|last = Quane|author2=Bottei, Rudolph S.|journal = Chemical Reviews|volume = 63|issue = 4|pages = 403–442|year =1963|doi = 10.1021/cr60224a004}}</ref> The organogermanium compound [[Propagermanium|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.<ref name="toxic" />
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).<ref>{{cite news|last=Broadwith|first=Phillip|title=Germanium-oxygen double bond takes centre stage|url=http://www.rsc.org/chemistryworld/News/2012/March/germanone-germanium-oxygen-double-bond-created.asp|accessdate=15 May 2014|newspaper=Chemistry World|date=25 March 2012}}</ref>
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== Izotopi ==
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<ref name="xpsstudy">{{cite journal|title=XPS study of the growth kinetics of thin films obtained by thermal oxidation of germanium substrates||author=Tabet, N; A.L Al-Oteibi; M.A Salim|year=1999|journal=Journal of Electron Spectroscopy and Related Phenomena|volume=101–103|page=233}}</ref>
<ref name="Coupling">{{cite journal|title=Oxidative Coupling of Deltahedral [Ge<sub>9</sub>]<sup>4−</sup> Zintl Ions|first = Li; Sevov Slavi C.|last = Xu|journal=J. Am. Chem. Soc.|year = 1999|volume = 121| issue = 39|pages = 9245–9246}} {{doi|10.1021/ja992269s}}</ref>
<!--********<ref name="Winkle2">{{cite journal|first = Clemens|last = Winkler |journal = J. Prak. Chemie|volume = 36|issue = 1|year = 1887 |pages = 177–209|title = Mittheilungen über des Germanium. Zweite Abhandlung|url = http://gallica.bnf.fr/ark:/12148/bpt6k90799n/f183.table| pristupdatum = 20.8.2008}} {{doi|10.1002/prac.18870360119}}</ref>-->
<!--********<ref name="toxic">{{cite journal|last = Tao|first = S. H.; Bolger, P. M.|date=juni 1997|title = Hazard Assessment of Germanium Supplements|journal = Regulatory Toxicology and Pharmacology|volume = 25|issue = 3|pages = 211–219}} {{doi|10.1006/rtph.1997.1098}}</ref> -->
<ref name="Aggarwal">{{cite journal|title = Infrared Transparent Germanate Glass-Ceramics|first = Shyam S.; Sanghera, Jasbinder S.; Aggarwal, Ishwar D.; Wojcik, Joshua A.|last = Bayya |journal = Journal of the American Ceramic Society|volume = 85|issue = 12|pages= 3114–3116|year = 2002}} {{doi|10.1111/j.1151-2916.2002.tb00594.x}}</ref>
<ref name="drugoveiko">{{cite journal|title = Infrared reflectance and transmission spectra of germanium dioxide and its hydrolysis products|year = 1975 |last = Drugoveiko|first = O. P.; Evstrop'ev, K. K.; Kondrat'eva, B. S.; Petrov, Yu. A.; Shevyakov A. M.|journal = Journal of Applied Spectroscopy|volume = 22|issue = 2|page = 191}} {{doi|10.1007/BF00614256}}</ref>
<ref name="BGO">{{cite journal|title = A Bismuth Germanate-Avalanche Photodiode Module Designed for Use in High Resolution Positron Emission Tomography|last = Lightstone|first = A. W.; McIntyre, R. J.; Lecomte, R.; Schmitt, D.|journal = IEEE Transactions on Nuclear Science| year = 1986|volume =33|issue= 1|pages = 456–459}} {{doi|10.1109/TNS.1986.4337142}}</ref>
<!--**********<ref name="Raman">{{cite journal|title = The Crystal Structure and Raman Spectrum of Ge<sub>5</sub>Cl<sub>12</sub>·GeCl<sub>4</sub> and the Vibrational Spectrum of Ge<sub>2</sub>Cl<sub>6</sub>| last = Beattie|first = I.R.; Jones, P.J.; Reid, G.; Webster, M.;|journal = Inorg. Chem.|volume = 37|issue =23|pages = 6032–6034|year = 1998}} {{doi|10.1021/ic9807341}}</ref>-->
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