Potassium dicyanoaurate

Potassium dicyanoaurate
	; Ball-and-stick model of the aurocyanide or dicyanoaurate(I) complex anion, [Au(CN)2]−.
Names
	Other names potassium dicyanoaurate(I)
Identifiers
CAS Number	13967-50-5;
3D model (JSmol)	Interactive image;
Beilstein Reference	6235525
ChEBI	CHEBI:30057;
ChemSpider	19988798;
ECHA InfoCard	100.034.303
EC Number	237-748-4;
Gmelin Reference	37363
PubChem CID	159710;
UNII	54L0T2BQF5;
UN number	1588
CompTox Dashboard (EPA)	DTXSID8044549 ;
	InChI InChI=1S/2CN.Au.K/c21-2;;/q2-1;2*+1 Key: XTFKWYDMKGAZKK-UHFFFAOYSA-N;
	SMILES [C-]#N.[C-]#N.[K+].[Au+];
Properties
Chemical formula	C2AuKN2
Molar mass	288.101 g·mol−1
Appearance	white powder
Boiling point	decomposes
Solubility in water	water-soluble
Hazards
	Occupational safety and health (OHS/OSH):
Main hazards	toxic
	GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H290, H300, H310, H315, H317, H318, H330, H410
Precautionary statements	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). Infobox references

Potassium dicyanoaurate, also potassium dicyanoaurate(I), potassium gold cyanide, potassium gold dicyanide or gold potassium cyanide, is an inorganic compound with formula K[Au(CN)₂]. It is a colorless to white crystalline powder, usually prepared by dissolving metallic gold in aqueous solution of potassium cyanide. It is most often used in gold plating applications. It contains 68.2 wt.% of gold. It is soluble in water and slightly soluble in alcohol.

Its CAS number is 13967-50-5 and its EC number number is 237-748-4. Its molar mass is 288.33 g/mol, its density is 3.45 g/cm³.

Potassium gold cyanide can be used for photoreduction of gold ions by nanopowder ZnO, preparation of gold-gold junction electrodes in voltammetric glucose detection,^[2] and other reactions where metallic gold is prepared.

A trivalent compound, potassium tetracyanoaurate(III), K[Au(CN)₄], also exists, but its use is less common.

The cyanide-gold complex penetrates cells much easier 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.^[3]

Gold mining

Potassium dicyanoaurate is produced in the cyanide process variant of gold mining.

The chemical reaction for the dissolution of gold, the "Elsner Equation", follows:

4 Au + 8 KCN + O₂ + 2H₂O → 4 K[Au(CN)₂] + 4 KOH

In this redox process, oxygen removes, via a two-step reaction, one electron from each gold atom to form the complex Au(CN)⁻
₂ ion.^[4]

References

^ Greenwood, N. N.; & Earnshaw, A. (1997). Chemistry of the Elements (2nd Edn.), Oxford:Butterworth-Heinemann. ISBN 0-7506-3365-4.
^ https://www.alfa.com/en/catalog/012552/
^ Wright, I. H.; Vesey, C. J. (September 1986). "Acute poisoning with gold cyanide". Anaesthesia. 41 (9): 936–939. doi:10.1111/j.1365-2044.1986.tb12920.x.
^ (Web Archive) Technical Bulletin, https://web.archive.org/web/20091023235047/http://www.multimix.com.au/DOCUMENTS/Technical%20Bulletin1.PDF

[1] Greenwood, N. N.; & Earnshaw, A. (1997). Chemistry of the Elements (2nd Edn.), Oxford:Butterworth-Heinemann. ISBN 0-7506-3365-4.

[2] ttps://www.alfa.com/en/catalog/012552/

[3] Wright, I. H.; Vesey, C. J. (September 1986). "Acute poisoning with gold cyanide". Anaesthesia. 41 (9): 936–939. doi:10.1111/j.1365-2044.1986.tb12920.x.

[4] (Web Archive) Technical Bulletin, https://web.archive.org/web/20091023235047/http://www.multimix.com.au/DOCUMENTS/Technical%20Bulletin1.PDF

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