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Germanium(II) hydroxide, normally written as Ge(OH)2, is a poorly characterised compound, sometimes called hydrous germanium(II) oxide or germanous hydroxide. It was first reported byWinkler in 1886.[1]
Germanium(II) hydroxide is formed as a white or yellow precipitate when base is added to solutions containing GeII, produced for example by the reduction of an acid solution ofgermanium dioxide, GeO2, withhypophosphorous acid, H3PO2,[2] or alternatively by hydrolysis of GeCl2.[3] The initial precipitate, which has no definite stoichiometry, can be represented by GeO·xH2O, Ge(OH)2·xH2O, or loosely Ge(OH)2. It is only slightly soluble in water or alkali[4] and not appreciably soluble inperchloric acid, HClO4,[2] but is soluble inhydrochloric acid, HCl.[2] On digestion withsodium hydroxide, NaOH, it yields a brown insoluble compound, which after dryingin vacuo forms a brownpyrophoric substance with the approximate stoichiometry of (HGe)2O3. On the basis of theinfrared spectrum, (HGe)2O3 may contain a germanium hydrogen bond, Ge-H.[4]