Potassium tetrabromoaurate

Potassium tetrabromoaurate(III) is a reddish-purple crystalline solid which begins to decompose at 120°.9 It is readily soluble in water, methanol, and ethanol. It slowly absorbs water from the atmosphere to form the 2-hydrate, which loses its water of hydration at 60°.6... 

Potassium tetrabromoaurate(l-) (0.3005 g, 0.541mmole)6 is placed in a 100-mL beaker containing a magnetic stirring bar. To this is added 20 mL HBr solution (0.1 M). L-Cysteine hydrochloride hydrate (available from Aldrich Chemical Co., Milwaukee, WI) (0.3120 g, 1.78mmole) is dissolved in a separate 100-mL beaker with 20 mL HBr (0.1 M). (The acid concentration is important. Use of 1 M HBr leads to a different product.) The CySH HCl H20 solution is rapidly added to the [AuBr4]" solution with constant stirring. 

Omrani H, Welter R, VangeUsti R (1999) Potassium tetrabromoaurate. Acta Cryst C55 13-14... 

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