Gold(I) chloride is a compound of
gold
Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile me ...
and
chlorine
Chlorine is a chemical element with the symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine i ...
with the
chemical formula
In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbol ...
AuCl.
Preparation
Gold(I) chloride is prepared by thermal decomposition of
gold(III) chloride
Gold(III) chloride, traditionally called auric chloride, is a compound of gold and chlorine with the molecular formula . The "III" in the name indicates that the gold has an oxidation state of +3, typical for many gold compounds. Gold(III) c ...
.
Reactions
Although there is a region of stability at higher temperatures at the appropriate chlorine vapor pressures, the compound is metastable at ambient conditions. When heated with water, the compound
disporpotionates to metallic gold and gold(III) chloride in an autoredox reaction:
: 3 AuCl → 2 Au + AuCl
3
At still higher temperatures, around 500 °C, all gold chlorides convert to gold. This conversion is key to the
Miller process, which is widely used for the purification of gold.
Reaction with
potassium bromide yields potassium auric bromide and
potassium chloride with separation of metallic gold:
: 3 AuCl + 4 KBr → KAuBr
4 + 2 Au + 3 KCl
Safety
Gold(I) chloride may irritate the skin and eyes, damage kidney function, and reduce white blood cell counts.
References
{{Chlorides
Gold(I) compounds
Chlorides
Metal halides
Gold–halogen compounds