Calcium cyanide

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Calcium cyanide
Calcium cyanide structure.svg
Names
IUPAC name
calcium dicyanide
Systematic IUPAC name
calcium dicyanide
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.008.856 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 209-740-0
PubChem CID
UNII
  • InChI=1S/2CN.Ca/c2*1-2;/q2*-1;+2
  • [Ca+2].[C-]#N.[C-]#N
Properties
Ca(CN)2
Molar mass 92.1128 g/mol
Appearancewhite powder
Odor hydrogen cyanide
Density 1.853 (20 °C)
Melting point 640 °C (1,184 °F; 913 K) (decomposes)
soluble
Solubility soluble in alcohol, weak acids
Structure
rhombohedric
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
Highly Toxic
NFPA 704 (fire diamond)
NFPA 704.svgHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 0: Will not burn. E.g. waterInstability 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g. calciumSpecial hazards (white): no code
3
0
1
Non-flammable
Lethal dose or concentration (LD, LC):
39 mg/kg rat, oral [1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Calcium cyanide is the inorganic compound with the formula Ca(CN)2. It is the calcium salt derived from hydrocyanic acid. It is a white solid, although the pure material is rarely encountered. It slowly hydrolyses in solution or moist air to release hydrogen cyanide and is very toxic. [3]

Contents

Preparation

Solutions of calcium cyanide can be prepared by treating calcium hydroxide with hydrogen cyanide. Solid calcium cyanide is produced commercially by heating calcium cyanamide with sodium chloride. The reaction is incomplete. The product is only of 50% purity, other components being sodium cyanide, calcium cyanamide, and carbon. Because of the carbon impurity, the solid is black, hence material is often called black cyanide. [3]

Reactivity

At temperatures around 600 °C, calcium cyanide converts to calcium cyanamide: [4] [5]

Ca(CN)2 → CaCN2 + C

It is suspected that this reaction is one step in the conversion of calcium carbide with nitrogen gas. The ratio of calcium cyanide to calcium cyanamide is sensitive to the presence of alkali metal halides, such as sodium chloride.

Calcium cyanide hydrolyzes upon acidification to form hydrogen cyanide:

Ca(CN)2 + 2 H+ → Ca2+ + 2 HCN

Calcium cyanide reacts with ammonium carbonate to give produce ammonium cyanide:

Ca(CN)2 + (NH4)2CO3 → 2 NH4CN + CaCO3

Uses

Calcium cyanide is used almost exclusively in the mining industry. It serves as an inexpensive source of cyanide in many leaching or vat operation to obtain precious metals such as gold and silver from their ores. [3] [6]

Safety

Like other cyanide salts, this compound is highly toxic and its use is strictly regulated.

Related Research Articles

<span class="mw-page-title-main">Cyanide</span> Any molecule with a cyano group (–C≡N)

In chemistry, cyanide is a chemical compound that contains a C≡N functional group. This group, known as the cyano group, consists of a carbon atom triple-bonded to a nitrogen atom.

<span class="mw-page-title-main">Potassium ferrocyanide</span> Chemical compound

Potassium hexacyanidoferrate(II) is the inorganic compound with formula K4[Fe(CN)6]·3H2O. It is the potassium salt of the coordination complex [Fe(CN)6]4−. This salt forms lemon-yellow monoclinic crystals.

<span class="mw-page-title-main">Sodium cyanide</span> Chemical compound

Sodium cyanide is a poisonous 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 moderately strong base.

<span class="mw-page-title-main">Calcium peroxide</span> Chemical compound

Calcium peroxide or calcium dioxide is the inorganic compound with the formula CaO2. It is the peroxide (O22−) salt of Ca2+. Commercial samples can be yellowish, but the pure compound is white. It is almost insoluble in water.

<span class="mw-page-title-main">Calcium sulfide</span> Chemical compound of formula CaS

Calcium sulfide is the chemical compound with the formula CaS. This white material crystallizes in cubes like rock salt. CaS has been studied as a component in a process that would recycle gypsum, a product of flue-gas desulfurization. Like many salts containing sulfide ions, CaS typically has an odour of H2S, which results from small amount of this gas formed by hydrolysis of the salt.

Dodecanol, or lauryl alcohol, is an organic compound produced industrially from palm kernel oil or coconut oil. It is a fatty alcohol. Sulfate esters of lauryl alcohol, especially sodium lauryl sulfate, are very widely used as surfactants. Sodium lauryl sulfate and the related dodecanol derivatives ammonium lauryl sulfate and sodium laureth sulfate are all used in shampoos. Dodecanol is tasteless, colorless, and has a floral odor.

<span class="mw-page-title-main">Calcium cyanamide</span> Chemical compound

Calcium cyanamide, also known as Calcium carbondiamide, Calcium cyan-2°-amide or Calcium cyanonitride is the inorganic compound with the formula CaCN2. It is the calcium salt of the cyanamide (CN2−
2
) anion. This chemical is used as fertilizer and is commercially known as nitrolime. It also has herbicidal activity and in the 1950s was marketed as cyanamid. It was first synthesized in 1898 by Adolph Frank and Nikodem Caro (Frank–Caro process).

<span class="mw-page-title-main">Potassium cyanate</span> Chemical compound

Potassium cyanate is an inorganic compound with the formula KOCN. It is a colourless solid. It is used to prepare many other compounds including useful herbicide. Worldwide production of the potassium and sodium salts was 20,000 tons in 2006.

<span class="mw-page-title-main">Ferricyanide</span> Anion in which a Fe3+ ion is complexed by 6 CN− ions

Ferricyanide is the anion [Fe(CN)6]3−. It is also called hexacyanoferrate(III) and in rare, but systematic nomenclature, hexacyanidoferrate(III). The most common salt of this anion is potassium ferricyanide, a red crystalline material that is used as an oxidant in organic chemistry.

<span class="mw-page-title-main">Ferrocyanide</span> Anion in which a Fe2+ ion is complexed by 6 CN− ions

Ferrocyanide is the name of the anion [Fe(CN)6]4−. Salts of this coordination complex give yellow solutions. It is usually available as the salt potassium ferrocyanide, which has the formula K4Fe(CN)6. [Fe(CN)6]4− is a diamagnetic species, featuring low-spin iron(II) center in an octahedral ligand environment. Although many salts of cyanide are highly toxic, ferro- and ferricyanides are less toxic because they tend not to release free cyanide. It is of commercial interest as a precursor to the pigment Prussian blue and, as its potassium salt, an anticaking agent.

<span class="mw-page-title-main">Cyanamide</span> Chemical compound featuring a nitrile group attached to an amino group

Cyanamide is an organic compound with the formula CN2H2. This white solid is widely used in agriculture and the production of pharmaceuticals and other organic compounds. It is also used as an alcohol-deterrent drug. The molecule features a nitrile group attached to an amino group. Derivatives of this compound are also referred to as cyanamides, the most common being calcium cyanamide (CaCN2).

<span class="mw-page-title-main">Sodium dichloroisocyanurate</span> Chemical compound

Sodium dichloroisocyanurate is a chemical compound widely used as a cleansing agent and disinfectant. It is a colorless, water-soluble solid, produced as a result of reaction of cyanuric acid with chlorine. The dihydrate is also known as is the potassium salt.

<span class="mw-page-title-main">Zinc cyanide</span> Chemical compound

Zinc cyanide is the inorganic compound with the formula Zn(CN)2. It is a white solid that is used mainly for electroplating zinc but also has more specialized applications for the synthesis of organic compounds.

<span class="mw-page-title-main">Andrussow process</span>

The Andrussow process is the dominant industrial process for the production of hydrogen cyanide. It involves the reaction of methane, ammonia, and oxygen. The process is catalyzed by a platinum-rhodium alloy.

2-Cyanoguanidine is a nitrile derived from guanidine. It is a dimer of cyanamide, from which it can be prepared. 2-Cyanoguanidine is a colourless solid that is soluble in water, acetone, and alcohol, but not nonpolar organic solvents.

<span class="mw-page-title-main">Triphenyltin chloride</span> Chemical compound

Triphenyltin chloride is an organotin compound with formula Sn(C6H5)3Cl. It is a colourless solid that dissolves in organic solvents. It slowly reacts with water. The main use for this compound is as a fungicide and antifoulant. Triphenyl tin chloride is used as a chemosterilant. Triphenyl tins used as an antifeedants against potato cutworm.

<span class="mw-page-title-main">Sodium ferrocyanide</span> Chemical compound

Sodium ferrocyanide is the sodium salt of the coordination compound of formula [Fe(CN)6]4−. In its hydrous form, Na4Fe(CN)6 · 10 H2O (sodium ferrocyanide decahydrate), it is sometimes known as yellow prussiate of soda. It is a yellow crystalline solid that is soluble in water and insoluble in alcohol. The yellow color is the color of ferrocyanide anion. Despite the presence of the cyanide ligands, sodium ferrocyanide has low toxicity (acceptable daily intake 0–0.025 mg/kg body weight). The ferrocyanides are less toxic than many salts of cyanide, because they tend not to release free cyanide. However, like all ferrocyanide salt solutions, addition of an acid or exposure to UV light can result in the production of hydrogen cyanide gas, which is extremely toxic.

Sodium cyanate is the inorganic compound with the formula NaOCN. A white solid, it is the sodium salt of the cyanate anion.

Potassium dicyanoaurate (or potassium gold cyanide) is an inorganic compound with formula K[Au(CN)2]. It is a colorless to white solid that is soluble in water and slightly soluble in alcohol. The salt itself is often not isolated, but solutions of the dicyanoaurate ion ([Au(CN)2]) are generated on a large scale in the extraction of gold from its ores.

Nickel dicyanide is the inorganic compound with a chemical formula Ni(CN)2. It is a gray-green solid that is insoluble in most solvents.

References

  1. "GESTIS-Stoffdatenbank". gestis-dguv-de. Retrieved 2022-04-16.
  2. "CALCIUM CYANIDE | CAMEO Chemicals | NOAA".
  3. 1 2 3 Gail, Ernst; Gos, Stephen; Kulzer, Rupprecht; Lorösch, Jürgen; Rubo, Andreas; Sauer, Manfred (2004). "Cyano Compounds, Inorganic". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi:10.1002/14356007.a08_159.pub2. ISBN   3527306730.
  4. "Production of Hydrocyanic Acid" United States Patent Office.1933.(accessed April 22, 2012).
  5. Thomas Güthner; Bernd Mertschenk (2006). "Cyanamides". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a08_139.pub2. ISBN   3527306730.
  6. "Use of Cyanide for the Gold Industry" International Cyanide Management Code for the Use of Cyanide in the Gold .2011. http://www.cyanidecode.org/cyanide_use.php Archived 2012-02-29 at the Wayback Machine (accessed April 22, 2012).