Gold(III) hydroxide, gold trihydroxide, or gold hydroxide is an

inorganic compound An inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds⁠that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as ''inorganic chemistry''. Inorgan ...

, a

hydroxide Hydroxide is a diatomic anion with chemical formula OH−. It consists of an oxygen and hydrogen atom held together by a single covalent bond, and carries a negative electric charge. It is an important but usually minor constituent of water. It ...

gold Gold is a chemical element; it has chemical symbol Au (from Latin ) and atomic number 79. In its pure form, it is a brightness, bright, slightly orange-yellow, dense, soft, malleable, and ductile metal. Chemically, gold is a transition metal ...

, with formula Au(OH)₃. It is also called auric acid with formula H₃AuO₃. It is easily dehydrated above 140 °C to

gold(III) oxide Gold(III) oxide (Au2O3) is an inorganic compound of gold and oxygen with the formula Au2O3. It is a red-brown solid that decomposes at 298 °C. According to X-ray crystallography, AuO features square planar gold centers with both 2- and 3-c ...

. Salts of auric acid are termed aurates. Gold hydroxide is used in medicine,

porcelain Porcelain (), also called china, is a ceramic material made by heating Industrial mineral, raw materials, generally including kaolinite, in a kiln to temperatures between . The greater strength and translucence of porcelain, relative to oth ...

making,

gold plating Gold plating is a method of depositing a thin layer of gold onto the surface of another metal, most often copper or silver (to make silver-gilt), by a chemical or electrochemical (electroplating) process. Plating refers to modern coating met ...

, and

daguerrotype Daguerreotype was the first publicly available photographic process, widely used during the 1840s and 1850s. "Daguerreotype" also refers to an image created through this process. Invented by Louis Daguerre and introduced worldwide in 1839, t ...

s. Gold hydroxide deposited on suitable carriers can be used for preparation of gold

catalyst Catalysis () is the increase in rate of a chemical reaction due to an added substance known as a catalyst (). Catalysts are not consumed by the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quick ...

s. Gold hydroxide is a product of electrochemical

corrosion Corrosion is a natural process that converts a refined metal into a more chemically stable oxide. It is the gradual deterioration of materials (usually a metal) by chemical or electrochemical reaction with their environment. Corrosion engine ...

of gold metalization subjected to moisture and positive electric potential; it is one of the corrosion failure modes of

microelectronics Microelectronics is a subfield of electronics. As the name suggests, microelectronics relates to the study and manufacture (or microfabrication) of very small electronic designs and components. Usually, but not always, this means micrometre ...

. Voluminous gold hydroxide is produced from gold metalization; after the layer grows thick it may

spall Spall are fragments of a material that are broken off a larger solid body. It can be produced by a variety of mechanisms, including as a result of projectile impact, corrosion, weathering, cavitation, or excessive rolling pressure (as in a ba ...

, and the conductive particles may cause short circuits or leakage paths. The decreased thickness of the gold layer may also lead to an increase in its electrical resistance, which can also lead to electrical failure.

Preparation and reactions

Gold(III) hydroxide is produced by the reaction of

chloroauric acid Chloroauric acid is an inorganic compound with the chemical formula . It forms hydrates . Both the trihydrate and tetrahydrate are known. Both are orange-yellow solids consisting of the planar anion. Often chloroauric acid is handled as a solutio ...

with an alkali, such as

sodium hydroxide Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula . It is a white solid ionic compound consisting of sodium cations and hydroxide anions . Sodium hydroxide is a highly corrosive base (chemistry), ...

: :HAuCl₄ + 4NaOH → Au(OH)₃ + 4NaCl + H₂O Gold(III) hydroxide reacts with ammonia to produce

fulminating gold Fulminating gold is a light- and shock-sensitive yellow to yellow-orange amorphous heterogeneous mixture of different polymeric compounds of predominantly gold(III), ammonia, and chlorine that cannot be described by a chemical formula. Here, " ful ...

, an explosive compound. It also reacts with an alkali to produce aurates(AuO₂⁻).

References

{{Hydroxides Gold(III) compounds Hydroxides