Hydrogen cyanide
The carbon atom (C) is triple bonded to the nitrogen atom (N). The compound melts at -14°C and boils at 26°C.
A simple way to produce the gas is by reduction of potassium ferrocyanide solution.
Hydrogen cyanide is weakly acidic and partly converts to the cyanide ion CN– in solution. Such a solution is called prussic acid or hydrocyanic acid.
An HCN concentration of 300 parts per million of air will kill a human in a few minutes. The toxicity is caused by the cyanide ion. The mechanism of this toxicity, and the uses of the poison, are described on the cyanide page.
Hydrogen cyanide (HCN), also known as formonitrile, is a colorless, volatile, and extremely poisonous chemical compound whose vapors have a bitter almond odor. It is produced in large quantities all over the world by the chemical industry where it is used in tempering steel, dyeing, explosives, engraving, the production of acrylic resin plastic, and other organic chemical products.
General
Name
Hydrogen cyanide
Chemical formula
HCN
Appearance
Colourless liquid
Physical
Formula weight
27.0 amu
Melting point
260 K (-13 °C)
Boiling point
299 K (26 °C)
Density
0.7 ×103 kg/m3
Solubility
very soluble
Thermochemistry
ΔfH0gas
135.14 kJ/mol
ΔfH0liquid
109 kJ/mol
ΔfH0solid
100 kJ/mol
S0gas, 1 bar
201.82 J/mol·K
S0liquid, 1 bar
113.01 J/mol·K
S0solid
? J/mol·K
Safety
Ingestion
Extremely toxic. Early symptoms include nausea, vomiting and abdominal pain.
Inhalation
Extremely dangerous. Early symptoms include slow breathing rate, irritation.
Skin
Poisoning is thought to be possible through the skin.
Eyes
Dilated pupils are a symptom of poisoning.
More info
Hazardous Chemical Database (http://ull.chemistry.uakron.edu/erd/chemicals/7/6581.html)
SI units were used where possible. Unless otherwise stated, standard conditions were used.