Germanium dichloride
Encyclopedia
Germanium dichloride is a chemical compound of germanium
Germanium
Germanium is a chemical element with the symbol Ge and atomic number 32. It is a lustrous, hard, grayish-white metalloid in the carbon group, chemically similar to its group neighbors tin and silicon. The isolated element is a semiconductor, with an appearance most similar to elemental silicon....

 and chlorine
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...

 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
Germanium tetrachloride
Germanium tetrachloride is a colourless liquid 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.-Production:...

, GeCl4, over Ge metal at 650°C.
GeCl4 + Ge → 2GeCl2

It is also formed from the decomposition of chlorogermane, GeH3Cl, at 70°C.
2 GeH3Cl → GeCl2 + GeH4 + H2

Reactions

GeCl2 is hydrolysed to give yellow germanium(II) hydroxide, which on warming gives brown germanium monoxide
Germanium monoxide
Germanium monoxide, GeO, is a chemical compound of germanium and oxygen. It can be prepared as a yellow sublimate at 1000°C by reacting GeO2 with Ge metal. The yellow sublimate turns brown on heating at 650°C.. GeO is not well characterised...

:
GeCl2 + 2H2O → Ge(OH)2 + 2HCl
Ge(OH)2 → GeO + H2O

Solutions of GeCl2 in HCl are strongly reducing. With chloride ion, ionic compounds containg the pyramidal GeCl3 ion have been characterised, for example With rubidium and caesium chloride compounds, e.g.RbGeCl3 are produced; these have distorted perovskite
Perovskite
A perovskite structure is any material with the same type of crystal structure as calcium titanium oxide , known as the perovskite structure, or XIIA2+VIB4+X2−3 with the oxygen in the face centers. Perovskites take their name from this compound, which was first discovered in the Ural mountains of...

 structures.

Molecular GeCl2, dichlorogermylene

Molecular GeCl2 is often called dichlorogermylene, highlighting its resemblance to a carbene
Carbene
In 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 RR'C:, but the carbon can instead be double-bonded to one group. The term "carbene" may also merely refer to the compound H2C:, also called...

. The structure of gas-phase molecular GeCl2 shows that it is a bent molecule, as predicted by VSEPR theory. 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.
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