Potassium dicyanoaurate is an inorganic compound with formula K[Au(CN)2]. It is a colorless to white solid that is soluble in water and slightly soluble in alcohol. The salt itself is often not isolated, but solutions of the dicyanoaurate ion ([Au(CN)2]−) are generated on a large scale in the extraction of gold from its ores.
potassium gold cyanide
potassium gold dicyanide
3D model (JSmol)
CompTox Dashboard (EPA)
|Molar mass||288.101 g·mol−1|
|Rhombohedral, hR54, No. 148|
a = 0.728 nm, b = 0.728 nm, c = 2.636 nm
Lattice volume (V)
Formula units (Z)
|Occupational safety and health (OHS/OSH):|
|H290, H300, H310, H315, H317, H318, H330, H410|
|P260, P264, P273, P280, P284, P301+P310|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
In mining of gold from dilute sources, gold is selectively extracted by dissolution in aqueous potassium cyanide. The reaction for the dissolution of gold, the "Elsner Equation", is:
In this process, oxygen is the oxidant.
It can also be produced by reaction of gold(I) salts with excess potassium cyanide.
Potassium dicyanoaurate is a salt. The dicyanoaurate anion is linear according to X-ray crystallography. On the basis of infrared spectroscopy, the dicyanoaurate anion adopts a very similar structure in sodium dicyanoaurate (NaAu(CN)2).
Dicyanoaurate is the soluble species that is the focus of gold cyanidation, the hydrometallurgical process for winning gold from dilute ores. In fact, sodium cyanide, not the potassium salt, is more widely used in commercial processes.
Aside from its major use as an intermediate in the extraction of gold, potassium dicyanoaurate is often used in gold plating applications.
Thet compound containing gold(III) cyanide is also known: potassium tetracyanoaurate(III), K[Au(CN)4]. Its use is less common.
The cyanide-gold complex penetrates cells much more easily than gold ions alone, facilitating gold toxicity. Gold inhibits activity of many enzymes, hindering detoxification of the cyanide ion to thiocyanate, potentiating the cyanide toxicity.