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Potassium cyanide

Potassium cyanide
Potassium-cyanide-phase-I-unit-cell-3D-SF.png
Names
IUPAC name
Potassium cyanide
Identifiers
151-50-8 YesY
3D model (Jmol) Interactive image
ChEBI CHEBI:33191 N
ChemSpider 8681 YesY
ECHA InfoCard 100.005.267
EC Number 205-792-3
PubChem 9032
RTECS number TS8750000
UNII MQD255M2ZO YesY
UN number 1680
Properties
KCN
Molar mass 65.12 g/mol
Appearance White crystalline solid
deliquescent
Odor faint, almond-like
Density 1.52 g/cm3
Melting point 634.5 °C (1,174.1 °F; 907.6 K)
Boiling point 1,625 °C (2,957 °F; 1,898 K)
71.6 g/100 ml (25 °C)
100 g/100 mL (100 °C)
Solubility in methanol 4.91 g/100 mL (20 °C)
Solubility in glycerol soluble
Solubility in formamide 14.6 g/100 mL
Solubility in ethanol 0.57 g/100mL
Solubility in hydroxylamine 41 g/100 mL
Acidity (pKa) 11.0
−37.0·10−6 cm3/mol
1.410
Thermochemistry
127.8 J K−1 mol−1
−131.5 kJ/mol
Hazards
Safety data sheet ICSC 0671
GHS pictograms The corrosion pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)The skull-and-crossbones pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)The health hazard pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)The environment pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
GHS signal word Danger
H290, H300, H310, H330, H370, H372, H410
P260, P264, P273, P280, P284, P301+310
Very Toxic T+ Dangerous for the Environment (Nature) N
R-phrases R26/27/28, R32, R50/53
S-phrases (S1/2), S7, S28, S29, S45, S60, S61
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 4: Very short exposure could cause death or major residual injury. E.g., VX gas Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
LD50 (median dose)
 5 mg/kg (oral, rabbit)
10 mg/kg (oral, rat)
5 mg/kg (oral, rat)
8.5 mg/kg (oral, mouse)
US health exposure limits (NIOSH):
PEL (Permissible)
 TWA 5 mg/m3
REL (Recommended)
 C 5 mg/m3 (4.7 ppm) [10-minute]
IDLH (Immediate danger)
 25 mg/m3
Related compounds
Other anions
Potassium cyanate
Potassium thiocyanate
Other cations
Sodium cyanide
Related compounds
 Hydrogen cyanide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YesYN ?)
Infobox references

Potassium cyanide is a compound with the formula KCN. This colorless crystalline salt, similar in appearance to sugar, is highly soluble in water. Most KCN is used in gold mining, organic synthesis, and electroplating. Smaller applications include jewelry for chemical gilding and buffing.

Potassium cyanide is highly toxic. The moist solid emits small amounts of hydrogen cyanide due to hydrolysis, which smells like bitter almonds. Not everyone, however, can smell this; the ability to do so is a genetic trait.

The taste of potassium cyanide has been described as acrid with a burning sensation.

KCN is produced by treating hydrogen cyanide with aqueous solution of potassium hydroxide, followed by evaporation of the solution in a vacuum:

or by treating formamide with potassium hydroxide:

About 50,000 tons of potassium cyanide are produced yearly.

Prior to 1900 AD, before the invention of the Castner process, potassium cyanide was the most important source of alkali metal cyanides. In this historical process, potassium cyanide was produced by decomposing potassium ferrocyanide:


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