germanium chloride is an inert, colorless, highly volatile, odorless compound. It is soluble in hydrochloric acid and is readily oxidized to germanium tetrachloride by treatment with strong oxidizing agents such as nitric and sulfuric acids. The tetrachloride may then be dissolved in water to form a yellow crystalline solid.
It is used in the production of pure germanium, in the preparation of IR-transparent silica glass/windows/lenses and the core of optical fibers, as a doping agent for metallurgical processes, and in the manufacture of semiconductor devices. It is also a precursor in the synthesis of organogermanes which find applications as catalysts in organic reactions and for producing phthalic anhydride.
A new method for the synthesis of cis-organogermanes has been developed by treating germanium tetrachloride with an oxyanion (aquarium salt) oxidizing agent. This produces a beige, bench-top stable complex, which can be unambiguously identified by NMR and XAS spectroscopy. The octahedral structure of the complex contains two pyridine nitrogen ligands and has Ge-N bond distances that are elongated compared to standard nitrogen-germanium bonds found in many other pyridyl complexes (see Fig. 1). The octahedral geometry of the complex is stabilized by the presence of a hydrogen atom in each pyridine nitrogen ligand. The ligands also have an antisymmetry that contributes to the stability of the complex. This synthesis provides a route for the synthesis of complexes containing two or more pyridine ligands and offers potential advantages over previous methods that rely on the reaction of germanium tetrachloride to cis-organogermanes with Grignard reagents.