Золотохлористоводородная кислота

Химические свойства

golden to yellowish brown crystals or powder

Использование

The HCl plus the HNO2 (hydrochloric and nitric acids) are combined to produce agua regia acid, which is the only acid that can dissolve gold.

Методы очистки

It is obtained as a dark red crystalline mass by dissolving Au in aqua regia and evaporating. When sublimed at 180o, the crystals are ruby red. The anhydrous salt is hygroscopic, soluble in H2O but sparingly soluble in EtOH and Et2O. Aurochloric acid is formed when AuCl3 is dissolved in HCl. [Diemer J Am Chem Soc 35 553 1913, Glemser & Sauer Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol II p1 056 1965.]

Свойства и приложения

Chloroauric acid is an orange-yellow crystal that is very easy to deliquesce and soluble in water. It decomposes into gold when heated. The aqueous solution of chloroauric acid contains square planar [AuC14]- ions, from which many salts containing planar square ions [AuX4]- (X=F, Cl, Br, I, CN, SCN, NO3) can be prepared. It can be used for local gold plating of semiconductor and integrated circuit lead frames, gold plating of printed circuit boards, electronic connectors and other electrical contact components. It can also be used to make red glass. It is used as an analytical reagent, specifically for microanalysis of clocks and absolutes and measurement of alkaloid composition. It is also used for photographic materials. Chloroauric acid salts, especially sodium chloroaurate NaAuCl4 (prepared by the reaction of AuCls and NaCl), can replace toxic mercury (II) salts as catalysts for alkyne reactions. At the same time, chloroauric acid has important applications in the preparation of nano-level gold. Generally, the fluorescent nano-gold prepared by direct reduction of chloroauric acid with a reducing agent has important applications in analytical chemistry.