Germanium(II) hydroxide, normally written as Ge(OH)2, is a poorly characterised compound, sometimes called hydrous germanium(II) oxide or germanous hydroxide.
[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 of germanium dioxide, GeO2, with hypophosphorous 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.
[2] On digestion with sodium hydroxide, NaOH, it yields a brown insoluble compound, which after drying in vacuo forms a brown pyrophoric substance with the approximate stoichiometry of (HGe)2O3.
On the basis of the infrared spectrum, (HGe)2O3 may contain a germanium hydrogen bond, Ge-H.[4]