4522. Chloroauric Acid

Nomenclature

CAS number: 16903-35-8
Hydrogen (SP-4-1)-tetrachloroaurate(1) (1:1); hydrochloroauric acid; aurochlorohydric acid; tetrachloroauric(III) acid; gold trichloride hydrochloride.
AuCl4H; mol wt 339.79.
Au 57.97%, Cl 41.74%, H 0.30%.
HAuCl4.

Description and references

Prepd according to the equation 2Au + 3Cl2 + 2HCl → 2HAuCl4: Thomsen, Ber. 16, 1585 (1883); Biltz, Wein, Z. Anorg. Allg. Chem. 148, 192 (1925).

Derivative

Trihydrate.

Nomenclature

CAS number: 16961-25-4
HAuCl4.3H2O; mol wt 393.83.
H 1.79%, Au 50.01%, Cl 36.01%, O 12.19%.

Derivative

Tetrahydrate.

Nomenclature

CAS number: 1303-50-0
HAuCl4.4H2O; mol wt 411.85.
H 2.20%, Au 47.82%, Cl 34.43%, O 15.54%.

Properties

Golden-yellow to reddish-yellow, very hygroscopic and deliquesc monoclinic crystals; readily affected by sunlight. (Also available as brown crystals or cryst masses, contg 50-51% gold, and having the same properties as the yellow crystals.) Has caustic action on the skin (blisters) and then on exposure to light leaves violet-brown spots. Dec on strong heating to Cl2, HCl, and metallic gold. d about 3.9. Very sol in water, alcohol; sol in ether. Keep tightly closed and protected from light.

Use

Photography, gold-plating, gilding glass and porcelain, manuf ruby glass; as a reagent for alkaloids. Graphite-furnace atomic absorption spectroscopy.