Germanium dichloride
Names
Preferred IUPAC name
Germanium dichloride
Systematic IUPAC name
Dichlorogermanylidene
Other names
Dichlorogermylene

Germanium(II) chloride

Germanous chloride
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.030.162
EC Number
  • 233-192-1
UNII
  • InChI=1S/Cl2Ge/c1-3-2
    Key: QHGIKMVOLGCZIP-UHFFFAOYSA-N
  • Cl[Ge]Cl
Properties
GeCl2
Molar mass 143.546 g/mol
Appearance white-pale yellow solid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

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.

Preparation

Solid germanium dichloride can be produced by comproportionation by passing germanium tetrachloride, GeCl4, over germanium metal at 300 °C and reduced pressure (0.1 mmHg).[1]

GeCl4 + Ge → 2 GeCl2

Germanium dichloride is also formed from the decomposition of trichlorogermane, GeHCl3, at 70 °C. Trichlorogermane is generated when germanium reacts with hydrogen chloride.[1] This reaction involves dehydrohalogenation.

GeHCl3 → GeCl2 + HCl

Another route to germanium dichloride is the reduction of germanium tetrachloride with hydrogen at 800 °C.[1]

GeCl4 + H2 → GeCl2 + 2HCl

Reactions

GeCl2 is hydrolysed to give yellow germanium(II) hydroxide, which on warming gives brown germanium monoxide:[1]

GeCl2 + 2 H2O ⇌ Ge(OH)2(s) + 2 HCl
Ge(OH)2 → GeO + H2O

Alkalizing a solution containing germanium(II) ions:

Ge2+ + 2 OH− → Ge(OH)2

Germanium oxides and hydroxides are amphoteric. Solutions of GeCl2 in HCl are strongly reducing.[2] With chloride ion, ionic compounds containing the pyramidal GeCl−3 ion have been characterised, for example [3] With rubidium and caesium chloride compounds, e.g. RbGeCl3 are produced; these have distorted perovskite structures.[1]

Germanium dichloride reacts with tetraethylammonium chloride to give the trichlorogermanate:[4]

GeCl2 + Et4NCl → Et4NGeCl3

Dichlorogermylene

Molecular GeCl2 is often called dichlorogermylene, highlighting its resemblance to a carbene. The structure of gas-phase molecular GeCl2 shows that it is a bent molecule, as predicted by VSEPR theory.[5] The dioxane complex, GeCl2·dioxane, has been used as a source of molecular GeCl2 for reaction syntheses, as has the in situ reaction of GeCl4 and Ge metal. GeCl2 is quite reactive and inserts into many types of chemical bonds.[6] Usually, germanium dichloride is generated from germanium dichloride dioxane.

References

  1. 1 2 3 4 5 Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 376. ISBN 978-0-08-037941-8.
  2. ↑ Egon Wiberg, Arnold Frederick Holleman (2001) Inorganic Chemistry, Elsevier ISBN 0-12-352651-5
  3. ↑ Kociok-Köhn, G.; Winter, J. G.; Filippou, A. C. (1999). "Trimethylphosphonium trichlorogermanate(II)". Acta Crystallogr. C. 55 (3): 351–353. doi:10.1107/S010827019801169X.
  4. ↑ Parshall, G. W. (1974). "Tetraethylammonium Trichlorogermanate(l-) and Trichlorostannate(l-)". Inorganic Syntheses. 15: 222–225. doi:10.1002/9780470132463.ch48. ISBN 9780470132463.
  5. ↑ Tsuchiya, Masaki J.; Honjou, Hiroaki; Tanaka, Keiichi; Tanaka, Takehiko (1995). "Millimeter-wave spectrum of germanium dichloride GeCl2. Equilibrium structure and anharmonic force field". Journal of Molecular Structure. 352–353: 407–415. Bibcode:1995JMoSt.352..407T. doi:10.1016/0022-2860(95)08830-O.
  6. ↑ Egorov, M.P.; Gaspar, P. (1994). "Germanium: Organometallic chemistry". Encyclopedia of Inorganic chemistry. John Wiley & Sons. ISBN 0-471-93620-0.
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