Germanium tetrachloride
2694431
181207008
2007-12-31T16:23:32Z
LordAnubisBOT
2572294
robot Adding: [[ar:رباعي كلوريد جيرمانيوم]]
{{Chembox new
| Name = Germanium tetrachloride
| ImageFile = Germanium-tetrachloride-2D.png
<!-- | ImageSize = 150px -->
| ImageName = Germanium tetrachloride
| ImageFile1 = Germanium-tetrachloride-3D-vdW.png
<!-- | ImageSize1 = 150px -->
| ImageName1 = Germanium tetrachloride
| IUPACName = Germanium(IV) chloride
| OtherNames = Germanium chloride<br /> Tetrachlorogermane
| Section1 = {{Chembox Identifiers
| CASNo = 10038-98-9
| RTECS = LY5220000
}}
| Section2 = {{Chembox Properties
| Formula = GeCl<sub>4</sub>
| MolarMass = 214.42 g/mol
| Appearance = colourless,<br /> fuming liquid
| Density = 1.84 g/cm³, liquid
| Solubility = hydrolyzes
| MeltingPt = −49.5 °C (223.65 K)
| BoilingPt = 83.1 °C (355–357 K)
| Viscosity =
}}
| Section3 = {{Chembox Structure
| MolShape = tetrahedral
| Dipole =
}}
| Section7 = {{Chembox Hazards
| ExternalMSDS = [https://fscimage.fishersci.com/msds/25041.htm "External MSDS"]
| MainHazards = React rapidly with water<br /> to form HCl and GeO<sub>2</sub>,<br /> corrosive,<br /> lachrymator
| NFPA-H = 3
| NFPA-F =
| NFPA-R = 2 | Other=<s>W</s>
| FlashPt = None
| RPhrases =
| SPhrases =
}}
| Section8 = {{Chembox Related
| OtherAnions = [[Germanium dichloride|GeCl<sub>2</sub>]], [[Germane|GeH<sub>4</sub>]], [[germanium dioxide|GeO<sub>2</sub>]], [[Silane|SiH<sub>4</sub>]]
}}
}}
'''Germanium tetrachloride''' is a colourless liquid used as an intermediate in the production of purified germanium metal. In recent years, GeCl<sub>4</sub> usage has increased substantially due to its use as a reagent for fiber optic production.
==Production==
Most commercial production of [[germanium]] is from treating flue-dusts of zinc- and copper-ore smelters, although a significant source is also found in the ash from the combustion of certain types of coal called vitrain. Germanium tetrachloride is an intermediate for the purification of germanium metal or its oxide, GeO<sub>2</sub>.<ref name=USGS>"Germanium" Mineral Commodity Profile, U.S. Geological Survey, 2005.</ref>
Germanium tetrachloride can be generated directly from GeO<sub>2</sub> by dissolution of the oxide in concentrated hydrchloric acid. The resulting mixture is fractionally distilled to purify and separate the germanium tetrachloride from other products and impurities.<ref name=CRC>"The Elements" C.R. Hammond, David R. Lide, ed. CRC Handbook of Chemistry and Physics, Edition 85 (CRC Press, Boca Raton, FL) (2004)</ref> The GeCl<sub>4</sub> can be rehydrolyzed with deionized water to produce pure GeO<sub>2</sub>, which is then reduced under hydrogen to produce germanium metal.<ref name=USGS>USGS</ref><ref name=CRC>CRC</ref>
Production of GeO<sub>2</sub>, however, is dependent on the oxidized form of germanium extracted from the ore. Copper-lead-sulfide and zinc-sulfide ores will produce GeS<sub>2</sub>, which is subsequently oxidized to GeO<sub>2</sub> with an oxidizer such as [[sodium chlorate]]. Zinc-ores are roasted and sintered and can produce the GeO<sub>2</sub> directly. The oxide is then processed as discussed above.<ref name=USGS>USGS</ref>
==Application==
Germanium tetrachloride is used almost exclusively as an intermediate for several optical processes. GeCl<sub>4</sub> can be directly hydrolyzed to GeO<sub>2</sub>, an oxide glass with several unique properties and applications, described below:
===Fiber Optics===
Most notable of GeO<sub>2</sub> is its high index of [[refraction]] and low optical dispersion, used for wide camera lens, microscopy, and for the core of fiber-optic lines.<ref name=CRC>CRC</ref> See [[Optical fiber]] for specifics on the manufacturing process. Overall, [[silicon tetrachloride]], SiCl<sub>4</sub> and germanium tetrachloride, GeCl<sub>4</sub> are introduced with [[oxygen]] into a hollow glass preform, which is carefully heated to allow for oxidation of the reagents to their respective oxides and formation of a glass mixture. The GeO<sub>2</sub> has a high index of refraction, so by varying the flowrate of germanium tetrachloride the overall index of refraction of the optical fiber can be specifically controlled. The GeO<sub>2</sub> is about 4% by weight of the glass.<ref name=USGS>USGS</ref>
===Infrared===
Germanium and its glass oxide, GeO<sub>2</sub> are transparent to the infrared spectrum. The glass can be manufactured into IR windows and lenses, used for night-vision technology in the military and luxury vehicles.<ref name=CRC>CRC</ref> GeO<sub>2</sub> is preferred over other IR transparent glasses because it is mechanically strong and therefore preferred for rugged military usage.<ref name=USGS>USGS</ref>
==Future==
As of the year 2000, about 15% of [[United States]] consumption of germanium is used for infrared optics technology and 50% for fiber-optics. Over the past 20 years, infrared use has consistently decreased; fiber optic demand, however, is slowly increasing. There is discussion on the over-production of fiber-optic networks and that 30-50% of current lines are unused "dark" fiber, suggesting a future reduction in demand. Worldwide, demand is increasing dramatically as countries such as China are expanding fiber-optic based telecommunication throughout the country.<ref name=USGS>USGS</ref>
==References==
<references/>
==See also==
* [[Germanium]]
* [[Optical fiber]]
* [[Infrared]]
[[Category:Germanium compounds]]
[[Category:Chlorides]]
[[Category:Nonmetal halides]]
[[ar:رباعي كلوريد جيرمانيوم]]