Germanium dichloride is a chemical compound of germanium and

chlorine Chlorine is a chemical element with the symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine i ...

with the formula . It is a yellow solid. Germanium dichloride is an example of a compound featuring germanium in the +2

oxidation state In chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom if all of its bonds to different atoms were fully ionic. It describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. C ...

Preparation

Solid germanium dichloride can be produced by

comproportionation Comproportionation or synproportionation is a chemical reaction where two reactants containing the same element but with different oxidation numbers, form a compound having an intermediate oxidation number. It is the opposite of disproportionation. ...

by passing

germanium tetrachloride Germanium tetrachloride is a colourless, fuming liquid 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 ...

, , over germanium metal at 300 °C and reduced pressure (0.1 mmHg). : Germanium dichloride is also formed from the decomposition of trichlorogermane, , at 70 °C. Trichlorogermane is generated when germanium reacts with hydrogen chloride. This reaction involves

dehydrohalogenation In chemistry, dehydrohalogenation is an elimination reaction which removes a hydrogen halide from a substrate. The reaction is usually associated with the synthesis of alkenes, but it has wider applications. Dehydrohalogenation from alkyl halid ...

. : Another route to germanium dichloride is the reduction of germanium tetrachloride with

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic ...

at 800 °C. :

Reactions

is hydrolysed to give yellow germanium(II) hydroxide, which on warming gives brown

germanium monoxide Germanium monoxide, GeO, is a chemical compound of germanium and oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmeta ...

: : : Alkalizing a solution containing germanium(II) ions: : Germanium oxides and hydroxides are amphoteric. Solutions of in HCl are strongly reducing.Egon Wiberg, Arnold Frederick Holleman (2001) ''Inorganic Chemistry'', Elsevier With chloride ion, ionic compounds containing the pyramidal ion have been characterised, for example With rubidium and caesium chloride compounds, e.g. are produced; these have distorted

perovskite Perovskite (pronunciation: ) is a calcium titanium oxide mineral composed of calcium titanate (chemical formula ). Its name is also applied to the class of compounds which have the same type of crystal structure as (XIIA2+VIB4+X2−3), known a ...

structures. Germanium dichloride reacts with tetraethylammonium chloride to give the trichlorogermanate: :

Dichlorogermylene

Molecular is often called dichlorogermylene, highlighting its resemblance to a

carbene In organic chemistry, a carbene is a molecule containing a neutral carbon atom with a valence of two and two unshared valence electrons. The general formula is or where the R represents substituents or hydrogen atoms. The term "carbene" ma ...

. The structure of gas-phase molecular shows that it is a bent molecule, as predicted by

VSEPR Valence shell electron pair repulsion (VSEPR) theory ( , ), is a model used in chemistry to predict the geometry of individual molecules from the number of electron pairs surrounding their central atoms. It is also named the Gillespie-Nyholm the ...

theory. The

dioxane 1,4-Dioxane () is a heterocyclic organic compound, classified as an ether. It is a colorless liquid with a faint sweet odor similar to that of diethyl ether. The compound is often called simply dioxane because the other dioxane isomers ( 1,2- ...

complex, , has been used as a source of molecular for reaction syntheses, as has the ''in situ'' reaction of and Ge metal. is quite reactive and inserts into many types of chemical bonds. Usually, germanium dichloride is generated from germanium dichloride dioxane.

References

{{Chlorides Germanium(II) compounds Chlorides Metal halides Nonmetal halides