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Sodium cyanide

 
Sodium Cyanide

 
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Sodium cyanide
 
 
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Sodium cyanide is the inorganic compound
Inorganic compound

Traditionally, inorganic compounds are considered to be of a mineral, not biological, origin. Complementarily, most organic compounds are traditionally viewed as being of biological origin....
 with the formula
Chemical formula

A chemical formula is a way of expressing information about the atoms that constitute a particular chemical compound, and how the relationship between those atoms changes in chemical reactions....
 NaCN. This highly toxic colourless salt is used mainly in gold mining
Gold mining

Gold mining consists of the processes and techniques employed in the resource extraction of gold from the ground. There are several techniques by which gold may be extracted from the Earth....
 but has other niche applications. It is the conjugate base of the weak acid
Weak acid

A weak acid is an acid that dissociates incompletely and does not release all of its hydrogens in a solution i.e it does not completely donate all of its protons....
 hydrogen cyanide
Hydrogen cyanide

Hydrogen cyanide is a chemical compound with chemical formula HCN. A solution of hydrogen cyanide in water is called hydrocyanic acid. Hydrogen cyanide is a colorless, extremely poisonous, and highly volatility liquid that boiling slightly above room temperature at 26 Celsius ....
.

um cyanide is produced by treating hydrogen cyanide with sodium hydroxide
Sodium hydroxide

Sodium hydroxide , also known as lye, caustic soda and sodium hydrate, is a caustic metallic Base . Sodium hydroxide forms a strong alkaline solution when dissolved in a solvent such as water, however, only the hydroxide ion is basic....
:
HCN + NaOH ? NaCN + H2O
Worldwide production was estimated at 500,000 tons in the year 2006.






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Encyclopedia


Sodium cyanide is the inorganic compound
Inorganic compound

Traditionally, inorganic compounds are considered to be of a mineral, not biological, origin. Complementarily, most organic compounds are traditionally viewed as being of biological origin....
 with the formula
Chemical formula

A chemical formula is a way of expressing information about the atoms that constitute a particular chemical compound, and how the relationship between those atoms changes in chemical reactions....
 NaCN. This highly toxic colourless salt is used mainly in gold mining
Gold mining

Gold mining consists of the processes and techniques employed in the resource extraction of gold from the ground. There are several techniques by which gold may be extracted from the Earth....
 but has other niche applications. It is the conjugate base of the weak acid
Weak acid

A weak acid is an acid that dissociates incompletely and does not release all of its hydrogens in a solution i.e it does not completely donate all of its protons....
 hydrogen cyanide
Hydrogen cyanide

Hydrogen cyanide is a chemical compound with chemical formula HCN. A solution of hydrogen cyanide in water is called hydrocyanic acid. Hydrogen cyanide is a colorless, extremely poisonous, and highly volatility liquid that boiling slightly above room temperature at 26 Celsius ....
.

Production and chemical properties

Sodium cyanide is produced by treating hydrogen cyanide with sodium hydroxide
Sodium hydroxide

Sodium hydroxide , also known as lye, caustic soda and sodium hydrate, is a caustic metallic Base . Sodium hydroxide forms a strong alkaline solution when dissolved in a solvent such as water, however, only the hydroxide ion is basic....
:
HCN + NaOH ? NaCN + H2O
Worldwide production was estimated at 500,000 tons in the year 2006. In former times, it was prepared by the Castner-Kellner process
Castner-Kellner process

The Castner-Kellner process is a method of electrolysis on an aqueous alkali chloride solution to produce the corresponding alkali hydroxide, invented by Hamilton Castner and Karl Kellner in the 1890s....
 involving the reaction of sodium amide
Sodium amide

Sodium amide, commonly called sodamide, is the chemical compound with the chemical formula NaNH2. This solid, which is dangerously reactive toward water, is white when pure, but commercial samples are typically gray due to the presence of small quantities of metallic iron from the manufacturing process....
 with carbon at elevated temperatures.
NaNH2 + C ? NaCN + H2


The structure of solid NaCN is related to that of sodium chloride
Sodium chloride

Sodium chloride, also known as common salt, table salt, or halite, is a chemical compound with the chemical formula SodiumChlorine....
. The anions and cations are each six-coordinate (KCN has a similar structure). Each Na+ forms pi-bonds to two CN- groups as well as two "bent" K---CN and two "bent "K---NC links.

Because the salt is derived from a weak acid, NaCN readily reverts back to HCN by hydrolysis
Hydrolysis

Hydrolysis is a chemical reaction during which one or more water are split into hydrogen and hydroxide ions which may go on to participate in further reactions....
: 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). 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
Hydrogen peroxide

Hydrogen peroxide is a very pale blue liquid which appears colorless in a dilute solution, slightly more viscous than water. It is a weak acid....
:
NaCN + H2O2 ? NaOCN
Cyanate

The cyanate ion is an anion consisting of one oxygen atom, one carbon atom, and one nitrogen atom, [OCN]-, in that order, and possesses 1 unit of negative electric charge, borne mainly by the nitrogen atom....
  + H2O


Applications


Cyanide mining

Sodium cyanide is mainly used to extract gold
Gold

Gold is a chemical element with the symbol Au and atomic number 79. It is a highly sought-after precious metal, having been used as money, as a store of value, in jewelry, in sculpture, and for ornamentation since the beginning of recorded history....
 and other precious metals in mining. This application exploits the high affinity of gold(I) for cyanide, which induces gold metal to oxidize and dissolve in the presence of air and water.
4 Au + 8 NaCN + O2 + 2 H2O ? 4 Na[Au(CN)2] + 4 NaOH
Few alternative methods exist for this extraction process.

Chemical feedstock

Several commercially significant chemical compounds are derived from cyanide, including cyanuric chloride
Cyanuric chloride

Cyanuric chloride is the chemical compound with the chemical formula 3. This colorless solid is the organochlorine derivative of 1,3,5-triazine....
, cyanogen chloride
Cyanogen chloride

Cyanogen chloride is an extremely toxic chemical compound with the chemical formula CNCl. This linear, triatomic pseudohalogen is an easily condensed colorless gas....
, and many nitrile
Nitrile

A nitrile is any organic compound which has a -Carbon=Nitrogen functional group. The -C=N functional group is called a nitrile group....
s. In organic synthesis
Organic synthesis

Organic synthesis is a special branch of chemical synthesis and is concerned with the construction of organic compounds via organic reactions. Organic_chemistry molecules can often contain a higher level of complexity compared to purely Inorganic_chemistry compounds, so the synthesis of organic compounds has developed into one of the most im...
, cyanide, which is classified as a strong nucleophile
Nucleophile

In chemistry, a nucleophile is a reagent that forms a chemical bond to its reaction partner by donating both bonding electrons. Because nucleophiles donate electrons, they are by definition Lewis bases ....
, is used to prepare nitrile
Nitrile

A nitrile is any organic compound which has a -Carbon=Nitrogen functional group. The -C=N functional group is called a nitrile group....
s, which occur widely in many specialty chemicals, including pharmaceuticals.

Niche uses

Being highly toxic, sodium cyanide is used to kill or stun rapidly such as in illegal cyanide fishing
Cyanide fishing

Cyanide fishing is an illegal form of fishing common in South East Asia, which usually uses the chemical compound sodium cyanide. Since 2000, increasing restrictions on illegal dynamite fishing have led to an increasing growth in this indiscriminate method ? particularly as it can be used without generating noise....
 and in collecting jars used by entomologists.

Toxicity

Cyanide salts are among the most rapidly acting of all known poisons. Cyanide is a potent inhibitor of respiration
Cellular respiration

Cellular respiration is the set of the metabolism reactions and processes that take place in organisms' cell s to convert Energy from nutrients into adenosine triphosphate , and then release waste products....
, acting on mitochondrial cytochrome oxidase and hence blocking electron transport. This results in decreased oxidative metabolism and oxygen utilization. Lactic acidosis then occurs as a consequence of anaerobic metabolism.

See also

  • Cyanide
    Cyanide

    A cyanide is any chemical compound that contains the nitrile , which consists of a carbon atom chemical bond to a nitrogen atom. Inorganic cyanides are hydrogen cyanide salts in which cyanide is generally the anion CN-....


External links

  • Institut national de recherche et de sécurité (1997). "". Fiche toxicologique n° 111, Paris:INRS, 6pp. (PDF file, in French)
  • (CICAD 61)