Sodium cyanide

Sodium cyanide
Sodium cyanide bonding
3D model (JSmol)
ECHA InfoCard100.005.091
EC Number205-599-4
RTECS numberVZ7525000
UN number1689
Molar mass49.0072 g/mol
Appearancewhite solid
Odorfaint almond-like
Density1.5955 g/cm3
Melting point563.7 °C (1,046.7 °F; 836.9 K)
Boiling point1,496 °C (2,725 °F; 1,769 K)
48.15 g/100 mL (10 °C)
63.7 g/100 mL (25 °C)
Solubilitysoluble in ammonia, methanol, ethanol
very slightly soluble in dimethylformamide, SO2
insoluble in dimethylsulphoxide
70.4 J/mol K
115.7 J/mol K
-91 kJ/mol
Safety data sheetICSC 1118
Very Toxic T+ Dangerous for the Environment (Nature) N Corrosive C [1]
R-phrases (outdated)R26/27/28, R32, R50/53
S-phrases (outdated)(S1/2), S7, S28, S29, S45, S60, S61
NFPA 704
Flash pointNon-flammable
Lethal dose or concentration (LD, LC):
6.44 mg/kg (rat, oral)
4 mg/kg (sheep, oral)
15 mg/kg (mammal, oral)
8 mg/kg (rat, oral)[3]
US health exposure limits (NIOSH):
PEL (Permissible)
TWA 5 mg/m3[2]
REL (Recommended)
C 5 mg/m3 (4.7 ppm) [10-minute][2]
IDLH (Immediate danger)
25 mg/m3 (as CN)[2]
Related compounds
Other cations
Potassium 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).
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Infobox references

Sodium cyanide is an inorganic compound with the formula NaCN. It is a white, water-soluble solid. Cyanide has a high affinity for metals, which leads to the high toxicity of this salt. Its main application, in gold mining, also exploits its high reactivity toward metals. It is a strong base. When treated with acid, it forms the toxic gas hydrogen cyanide:

NaCN + H2SO4 → HCN + NaHSO4

Production and chemical properties

Sodium cyanide is produced by treating hydrogen cyanide with sodium hydroxide:[4]

HCN + NaOH → NaCN + H2O

Worldwide production was estimated at 500,000 tons in the year 2006. Formerly it was prepared by the Castner process involving the reaction of sodium amide with carbon at elevated temperatures.

NaNH2 + C → NaCN + H2

The structure of solid NaCN is related to that of sodium chloride.[5] The anions and cations are each six-coordinate. Potassium cyanide (KCN) adopts a similar structure. Each Na+ forms pi-bonds to two CN groups as well as two "bent" Na---CN and two "bent" Na---NC links.[6]

Because the salt is derived from a weak acid, sodium cyanide readily reverts to HCN by hydrolysis; the moist solid emits small amounts of hydrogen cyanide, which smells like bitter almonds (not everyone can smell it—the ability thereof is due to a genetic trait[7]). Sodium cyanide reacts rapidly with strong acids to release hydrogen cyanide. This dangerous process represents a significant risk associated with cyanide salts. It is detoxified most efficiently with hydrogen peroxide (H2O2) to produce sodium cyanate (NaOCN) and water:[4]

NaCN + H2O2 → NaOCN + H2O
Other Languages
bosanski: Natrij-cijanid
čeština: Kyanid sodný
Deutsch: Natriumcyanid
Esperanto: Natria cianido
Кыргызча: Натрий цианиди
Nederlands: Natriumcyanide
polski: Cyjanek sodu
português: Cianeto de sódio
slovenščina: Natrijev cianid
српски / srpski: Natrijum cijanid
srpskohrvatski / српскохрватски: Natrijum cijanid
svenska: Natriumcyanid
اردو: Sodium cyanide
Tiếng Việt: Natri xyanua
中文: 氰化钠