Germanium tetrachloride

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Germanium tetrachloride
Germanium(IV)-chlorid in einem Schlenkrohr..jpg
Germanium tetrachloride - structural formula Germanium-tetrachloride-2D.png
Germanium tetrachloride - structural formula
Germanium tetrachloride - space-filling model Germanium-tetrachloride-3D-vdW.png
Germanium tetrachloride - space-filling model
Names
IUPAC names
Germanium tetrachloride
Tetrachlorogermane
Tetrachloridogermanium
Other names
Germanium(IV) chloride
Neutral germanium chloride (1:4)
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.030.093 OOjs UI icon edit-ltr-progressive.svg
PubChem CID
RTECS number
  • LY5220000
UNII
  • InChI=1S/Cl4Ge/c1-5(2,3)4 Yes check.svgY
    Key: IEXRMSFAVATTJX-UHFFFAOYSA-N Yes check.svgY
  • InChI=1S/Cl4Ge/c1-5(2,3)4
    Key: IEXRMSFAVATTJX-UHFFFAOYSA-N
  • Cl[Ge](Cl)(Cl)Cl
Properties
GeCl4
Molar mass 214.40 g/mol
AppearanceColourless liquid
Density 1.879 g/cm3 (20 °C)
1.844 g/cm3 (30 °C) [1]
Melting point −49.5 °C (−57.1 °F; 223.7 K)
Boiling point 86.5 °C (187.7 °F; 359.6 K)
Soluble, hydrolyses
Solubility Soluble in ether, benzene, chloroform, CCl4
Very soluble in HCl, dilute H2SO4
72.0·10−6 cm3/mol
1.464
Structure
tetrahedral [2]
Thermochemistry [3]
Std molar
entropy
(S298)
245.6 J·mol−1·K−1
−531.8 kJ·mol−1
−462.7 kJ·mol−1
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
Reacts slowly with water to form HCl and GeO2, corrosive, lachrymator
NFPA 704 (fire diamond)
NFPA 704.svgHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 0: Will not burn. E.g. waterInstability 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g. white phosphorusSpecial hazard W: Reacts with water in an unusual or dangerous manner. E.g. sodium, sulfuric acid
3
0
2
W
Flash point Non-flammable
Safety data sheet (SDS) "External MSDS"
Related compounds
Other anions
Germanium tetrafluoride
Germanium tetrabromide
Germanium tetraiodide
Other cations
Carbon tetrachloride
Silicon tetrachloride
Tin(IV) chloride
Lead(IV) chloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Yes check.svgY  verify  (what is  Yes check.svgYX mark.svgN ?)

Germanium tetrachloride is a colourless, fuming liquid [4] with a peculiar, acidic odour. It is used as an intermediate in the production of purified germanium metal. In recent years, GeCl4 usage has increased substantially due to its use as a reagent for fiber optic production.

Contents

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, GeO2. [5]

Germanium tetrachloride can be generated directly from GeO2 (germanium dioxide) by dissolution of the oxide in concentrated hydrochloric acid. The resulting mixture is fractionally distilled to purify and separate the germanium tetrachloride from other products and impurities. [6] The GeCl4 can be rehydrolysed with deionized water to produce pure GeO2, which is then reduced under hydrogen to produce germanium metal. [5] [6]

Production of GeO2, however, is dependent on the oxidized form of germanium extracted from the ore. Copper-lead-sulfide and zinc-sulfide ores will produce GeS2, which is subsequently oxidized to GeO2 with an oxidizer such as sodium chlorate. Zinc-ores are roasted and sintered and can produce the GeO2 directly. The oxide is then processed as discussed above. [5]

The classic synthesis from chlorine and germanium metal at elevated temperatures is also possible. [7] [1] Additionally, a chlorine free activation of germanium has been developed, giving a less energy intensive and more environmentally friendly alternative synthesis for germanium precursors.

Application

Germanium tetrachloride is used almost exclusively as an intermediate for several optical processes. GeCl4 can be directly hydrolysed to GeO2, an oxide glass with several unique properties and applications, described below and in linked articles:

Fiber optics

A notable derivative of GeCl4 is germanium dioxide. In the manufacture of optical fibers, silicon tetrachloride, SiCl4, and germanium tetrachloride, GeCl4, 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 GeO2 has a high index of refraction, so by varying the flow rate of germanium tetrachloride the overall index of refraction of the optical fiber can be specifically controlled. The GeO2 is about 4% by weight of the glass. [5]

Related Research Articles

<span class="mw-page-title-main">Germanium</span> Chemical element, symbol Ge and atomic number 32

Germanium is a chemical element with the symbol Ge and atomic number 32. It is lustrous, hard-brittle, grayish-white and similar in appearance to silicon. It is a metalloid 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.

<span class="mw-page-title-main">Indium</span> Chemical element, symbol In and atomic number 49

Indium is a chemical element with the symbol In and atomic number 49. Indium is the softest metal that is not an alkali metal. It is a silvery-white metal that resembles tin in appearance. It is a post-transition metal that makes up 0.21 parts per million of the Earth's crust. Indium has a melting point higher than sodium and gallium, but lower than lithium and tin. Chemically, indium is similar to gallium and thallium, and it is largely intermediate between the two in terms of its properties. Indium was discovered in 1863 by Ferdinand Reich and Hieronymous Theodor Richter by spectroscopic methods. They named it for the indigo blue line in its spectrum. Indium was isolated the next year.

<span class="mw-page-title-main">Manganese dioxide</span> Chemical compound

Manganese dioxide is the inorganic compound with the formula MnO
2
. This blackish or brown solid occurs naturally as the mineral pyrolusite, which is the main ore of manganese and a component of manganese nodules. The principal use for MnO
2
is for dry-cell batteries, such as the alkaline battery and the zinc–carbon battery. MnO
2
is also used as a pigment and as a precursor to other manganese compounds, such as KMnO
4
. It is used as a reagent in organic synthesis, for example, for the oxidation of allylic alcohols. MnO
2
has an α-polymorph that can incorporate a variety of atoms in the "tunnels" or "channels" between the manganese oxide octahedra. There is considerable interest in α-MnO
2
as a possible cathode for lithium-ion batteries.

<span class="mw-page-title-main">Silicon tetrachloride</span> Chemical compound

Silicon tetrachloride or tetrachlorosilane is the inorganic compound with the formula SiCl4. It is a colorless volatile liquid that fumes in air. It is used to produce high purity silicon and silica for commercial applications. It is a part of the chlorosilane family.

Iron(III) chloride describes the inorganic compounds with the formula FeCl3(H2O)x. Also called ferric chloride, these compounds are available both in anhydrous and hydrated forms which are both hygroscopic. They are common sources of iron in its +3 oxidation state. The anhydrous derivative is a Lewis acid, while the hydrate is a mild oxidizing agent. It is used as a water cleaner and as an etchant for metals.

<span class="mw-page-title-main">Zinc chloride</span> Chemical compound

Zinc chloride is the name of inorganic chemical compounds with the formula ZnCl2. It forms hydrates. Zinc chloride, anhydrous and its hydrates are colorless or white crystalline solids, and are highly soluble in water. Five hydrates of zinc chloride are known, as well as four forms of anhydrous zinc chloride. This salt is hygroscopic and even deliquescent. Zinc chloride finds wide application in textile processing, metallurgical fluxes, and chemical synthesis. No mineral with this chemical composition is known aside from the very rare mineral simonkolleite, Zn5(OH)8Cl2·H2O.

<span class="mw-page-title-main">Lead(II) chloride</span> Chemical compound

Lead(II) chloride (PbCl2) is an inorganic compound which is a white solid under ambient conditions. It is poorly soluble in water. Lead(II) chloride is one of the most important lead-based reagents. It also occurs naturally in the form of the mineral cotunnite.

<span class="mw-page-title-main">Copper(II) chloride</span> Chemical compound

Copper(II) chloride, also known as cupric chloride, is an inorganic compound with the chemical formula CuCl2. The monoclinic yellowish-brown anhydrous form slowly absorbs moisture to form the orthorhombic blue-green dihydrate CuCl2·2H2O, with two water molecules of hydration. It is industrially produced for use as a co-catalyst in the Wacker process.

Calcium hypochlorite is an inorganic compound with formula Ca(ClO)2. It is a white solid, although commercial samples appear yellow. It strongly smells of chlorine, owing to its slow decomposition in moist air. This compound is relatively stable as a solid and solution and has greater available chlorine than sodium hypochlorite. "Pure" samples have 99.2% active chlorine. Given common industrial purity, an active chlorine content of 65-70% is typical. It is the main active ingredient of commercial products called bleaching powder, used for water treatment and as a bleaching agent.

Boron trichloride is the inorganic compound with the formula BCl3. This colorless gas is a reagent in organic synthesis. It is highly reactive toward water.

Germanium dioxide, also called germanium(IV) oxide, germania, and salt of germanium, is an inorganic compound with the chemical formula GeO2. It is the main commercial source of germanium. It also forms as a passivation layer on pure germanium in contact with atmospheric oxygen.

<span class="mw-page-title-main">Gallium trichloride</span> Chemical compound

Gallium trichloride is the chemical compound with the formula GaCl3. Solid gallium trichloride exists as a dimer with the formula Ga2Cl6. It is colourless and soluble in virtually all solvents, even alkanes, which is truly unusual for a metal halide. It is the main precursor to most derivatives of gallium and a reagent in organic synthesis.

The chloride process is used to separate titanium from its ores. The goal of the process is to win high purity titanium dioxide from ores such as ilmenite (FeTiO3) and rutile (TiO2). The strategy exploits the volatility of TiCl4, which is readily purified and converted to the dioxide. Millions of tons of TiO2 are produced annually by this process, mainly for use as white pigments. The chloride process has largely displaced the older sulfate process, which relies on hot sulfuric acid to extract iron and other impurities from ores..

<span class="mw-page-title-main">Germanium dichloride</span> Chemical compound

Germanium dichloride is a chemical compound of germanium and chlorine with the formula GeCl2. It is a yellow solid. Germanium dichloride is an example of a compound featuring germanium in the +2 oxidation state.

<span class="mw-page-title-main">Lead compounds</span> Type of compound

Compounds of lead exist with lead in two main oxidation states: +2 and +4. The former is more common. Inorganic lead(IV) compounds are typically strong oxidants or exist only in highly acidic solutions.

<span class="mw-page-title-main">Germanium monosulfide</span> Chemical compound

Germanium monosulfide or Germanium(II) sulfide is the chemical compound with the formula GeS. It is a chalcogenide glass and a semiconductor. Germanium sulfide is described as a red-brown powder or black crystals. Germanium(II) sulfide when dry is stable in air, hydrolyzes slowly in moist air but rapidly reacts in water forming Ge(OH)2 and then GeO. It is one of a few sulfides that can be sublimed under vacuum without decomposition.

The +4 oxidation state dominates titanium chemistry, but compounds in the +3 oxidation state are also numerous. Commonly, titanium adopts an octahedral coordination geometry in its complexes, but tetrahedral TiCl4 is a notable exception. Because of its high oxidation state, titanium(IV) compounds exhibit a high degree of covalent bonding.

Germanium compounds are chemical compounds formed by the element germanium (Ge). Germanium is insoluble in dilute acids and alkalis but dissolves slowly in hot concentrated sulfuric and nitric acids and reacts violently with molten alkalis to produce germanates ([GeO
3
]2−
). Germanium occurs mostly in the oxidation state +4 although many +2 compounds are known. Other oxidation states are rare: +3 is found in compounds such as Ge2Cl6, and +3 and +1 are found on the surface of oxides, or negative oxidation states in germanides, such as −4 in Mg
2
Ge
. 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. The oxidation states of the element in these ions are not integers—similar to the ozonides O3.

<span class="mw-page-title-main">Chlorine-free germanium processing</span>

Chlorine-free germanium processing are methods of germanium activation to form useful germanium precursors in a more energy efficient and environmentally friendly way compared to traditional synthetic routes. Germanium tetrachloride is a valuable intermediate for the synthesis of many germanium complexes. Normal synthesis of it involves an energy-intensive dehydration of germanium oxide, , with hydrogen chloride, Due to the environmental and safety impact of non-recyclable, high energy reactions with , an alternative synthesis of a shelf-stable germanium intermediate precursor without chlorine is of interest. In 2017, a synthesis of organogermanes, without using chloride species was reported, allowing for a much more environmentally friendly and low energy synthesis using , , and even selectively activating germanium in the presence of zinc oxide, resulting in products that are bench stable and solid.

References

  1. 1 2 P.W. Schenk (1963). "Germanium(IV) Chloride". In G. Brauer (ed.). Handbook of Preparative Inorganic Chemistry, 2nd Ed. Vol. 1. NY,NY: Academic Press. pp. 715–716.
  2. Merz, K.; Driess, M. (2002). "Germanium(IV) chloride at 193 K". Acta Crystallogr. C . 58 (Pt 7): i101–i102. doi:10.1107/S0108270102010351. PMID   12094027.
  3. CRC handbook of chemistry and physics : a ready-reference book of chemical and physical data. William M. Haynes, David R. Lide, Thomas J. Bruno (2016-2017, 97th ed.). Boca Raton, Florida. 2016. ISBN   978-1-4987-5428-6. OCLC   930681942.{{cite book}}: CS1 maint: location missing publisher (link) CS1 maint: others (link)
  4. Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 377. ISBN   978-0-08-037941-8.
  5. 1 2 3 4 "Germanium" Mineral Commodity Profile, U.S. Geological Survey, 2005.
  6. 1 2 "The Elements" C. R. Hammond, David R. Lide, ed. CRC Handbook of Chemistry and Physics, Edition 85 (CRC Press, Boca Raton, Florida) (2004)
  7. "GeCl4 synthesis". account.e.jimdo.com. Technische Universitä Ilmenau. Retrieved 2020-09-22.

See also