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 by
Winkler in 1886.
Properties and preparation
Germanium(II) hydroxide is formed as a white or yellow precipitate when base is added to solutions containing Ge
II, produced for example by the reduction of an acid solution of
germanium dioxide
Germanium dioxide, also called germanium(IV) oxide, germania, and salt of germanium, is an inorganic compound with the chemical formula Ge O2. It is the main commercial source of germanium. It also forms as a passivation layer on pure germaniu ...
, GeO
2, with
hypophosphorous acid
Hypophosphorous acid (HPA), or phosphinic acid, is a phosphorus oxyacid and a powerful reducing agent with molecular formula H3PO2. It is a colorless low-melting compound, which is soluble in water, dioxane
and alcohols. The formula for this ...
, H
3PO
2,
or alternatively by hydrolysis of GeCl
2.
The initial precipitate, which has no definite stoichiometry, can be represented by GeO·''x''H
2O, Ge(OH)
2·''x''H
2O, or loosely Ge(OH)
2. It is only slightly soluble in water or alkali
and not appreciably soluble in
perchloric acid
Perchloric acid is a mineral acid with the formula H Cl O4. Usually found as an aqueous solution, this colorless compound is a stronger acid than sulfuric acid, nitric acid and hydrochloric acid. It is a powerful oxidizer when hot, but aqueous s ...
, HClO
4,
but is soluble in
hydrochloric acid
Hydrochloric acid, also known as muriatic acid, is an aqueous solution of hydrogen chloride. It is a colorless solution with a distinctive pungent smell. It is classified as a strong acid
Acid strength is the tendency of an acid, symbol ...
, HCl.
On digestion with
sodium hydroxide, NaOH, it yields a brown insoluble compound, which after drying ''in vacuo'' forms a brown
pyrophoric
A substance is pyrophoric (from grc-gre, πυροφόρος, , 'fire-bearing') if it ignites spontaneously in air at or below (for gases) or within 5 minutes after coming into contact with air (for liquids and solids). Examples are organolit ...
substance with the approximate stoichiometry of (HGe)
2O
3. On the basis of the
infrared
Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
spectrum, (HGe)
2O
3 may contain a germanium hydrogen bond, Ge-H.
References
{{Hydroxides
Germanium(II) compounds
Hydroxides