Germanium dichloride

Germanium dichloride
Preferred IUPAC name Germanium dichloride
Systematic name Dichlorogermanylidene
Other names Dichlorogermylene Germanium(II) chloride Germanous chloride
Identifiers
CAS number	10060-11-4
PubChem	6327122 Y
ChemSpider	4885679 Y
EC number	233-192-1
Jmol-3D images	Image 1
SMILES Cl[Ge]Cl
InChI InChI=1S/Cl2Ge/c1-3-2 Key: QHGIKMVOLGCZIP-UHFFFAOYSA-N
Properties
Molecular formula	GeCl2
Molar mass	143.546 g/mol
Appearance	white-pale yellow solid
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

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

Preparation

Solid GeCl₂ can be produced by passing germanium tetrachloride, GeCl₄, over Ge metal at 650°C.^[1]

GeCl₄ + Ge → 2GeCl₂

It is also formed from the decomposition of chlorogermane, GeH₃Cl, at 70°C.^[1]

2 GeH₃Cl → GeCl₂ + GeH₄ + H₂

Reactions

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

GeCl₂ + 2H₂O → Ge(OH)₂ + 2HCl

Ge(OH)₂ → GeO + H₂O

Solutions of GeCl₂ in HCl are strongly reducing.^[2] With chloride ion, ionic compounds containg the pyramidal GeCl₃⁻ ion have been characterised, for example ^[3] With rubidium and caesium chloride compounds, e.g.RbGeCl₃ are produced; these have distorted perovskite structures. ^[1]

Molecular GeCl₂, 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.^[4] 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 different types of chemical bonds.^[5]

References

1. ^ ^{a b c d} Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Oxford: Butterworth-Heinemann. ISBN 0080379419. 
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 Cryst. C55 (3): 351–353. doi:10.1107/S010827019801169X. 
4. ^ 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. doi:10.1016/0022-2860(95)08830-O. 
5. ^ Egorov, M.P.; Gaspar, P. (1994). "Germanium: Organometallic chemistry". Encyclopedia of Inorganic chemistry. John Wiley & Sons. ISBN 0-471-93620-0.