Zinc cyanide

Last updated
Zinc cyanide
Cd(CN)2.jpg
Names
Other names
Neutral zinc cyanide (1:2)
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.008.331 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 209-162-9
PubChem CID
RTECS number
  • ZH1575000
UNII
UN number 1713
  • InChI=1S/2CN.Zn/c2*1-2;/q2*-1;+2 Yes check.svgY
    Key: GTLDTDOJJJZVBW-UHFFFAOYSA-N Yes check.svgY
  • InChI=1/2CN.Zn/c2*1-2;/q2*-1;+2
    Key: GTLDTDOJJJZVBW-UHFFFAOYAM
  • [Zn+2].[C-]#N.[C-]#N
Properties
Zn(CN)2
Molar mass 117.444 g/mol
Appearancewhite solid
Density 1.852 g/cm3, solid
Melting point 800 °C (1,470 °F; 1,070 K) (decomposes)
0.0005 g/100 mL (20 °C)
Solubility attacked by alkalies, KCN, ammonia
−46.0·10−6 cm3/mol
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
Toxic, releases cyanide-ion in body [1]
GHS labelling: [2]
GHS-pictogram-skull.svg GHS-pictogram-pollu.svg
Danger
H300, H301, H310, H330, H410
P260, P262, P264, P270, P271, P273, P280, P284, P301+P310, P302+P350, P304+P340, P310, P320, P322, P330, P361, P363, P391, P403+P233, P405, P501
NFPA 704 (fire diamond)
3
0
0
Lethal dose or concentration (LD, LC):
100 mg/kg, rat (intraperitoneal)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)

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.

Contents

Structure

In Zn(CN)2, zinc adopts the tetrahedral coordination environment, all linked by bridging cyanide ligands. The structure consists of two "interpenetrating" structures (blue and red in the picture above). Such motifs are sometimes called "expanded diamondoid" structures. Some forms of SiO2 adopt a similar structure, wherein the tetrahedral Si centres are linked by oxides. The cyanide group shows head to tail disorder with any zinc atom having between one and four carbon neighbours, and the remaining being nitrogen atoms. [4] It shows one of the largest negative coefficients of thermal expansion (exceeding the previous record holder, zirconium tungstate).

Chemical properties

Typical for an inorganic polymer, Zn(CN)2 is insoluble in most solvents. The solid dissolves in, or more precisely, is degraded by, aqueous solutions of basic ligands such as hydroxide, ammonia, and additional cyanide to give anionic complexes.

Synthesis

Zn(CN)2 is easy to make by combining aqueous solutions of cyanide and zinc ions, for example via the double replacement reaction between KCN and ZnSO4: [5]

ZnSO4 + 2 KCN → Zn(CN)2 + K2SO4

For commercial applications, some effort is made to avoid halide impurities by using acetate salts of zinc: [5] [6]

Zn(CH3COO)2 + HCN → Zn(CN)2 + 2 CH3COOH

Zinc cyanide is also produced as a byproduct of certain gold extraction methods. Procedures to isolate gold from aqueous gold cyanide sometimes call for the addition of zinc:

2 [Au(CN)2]− + Zn → 2 Au + Zn(CN)2 + 2 CN−

Applications

Electroplating

The main application of Zn(CN)2 is for electroplating of zinc from aqueous solutions containing additional cyanide. [6]

Organic synthesis

Zn(CN)2 is used to introduce the formyl group in to aromatic compounds in the Gatterman reaction where it serves a convenient, safer, and non-gaseous alternative to HCN. [7] Because the reaction uses HCl, Zn(CN)2 also supplies the reaction in situ with ZnCl2, a Lewis acid catalyst. Examples of Zn(CN)2 being used in this way include the synthesis of 2-hydroxy-1-naphthaldehyde and mesitaldehyde. [8]

Zn(CN)2 is also employed as a catalyst for the cyanosilylation of aldehydes and ketones. [9]

Related Research Articles

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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">Potassium ferricyanide</span> Chemical compound

Potassium ferricyanide is the chemical compound with the formula K3[Fe(CN)6]. This bright red salt contains the octahedrally coordinated [Fe(CN)6]3− ion. It is soluble in water and its solution shows some green-yellow fluorescence. It was discovered in 1822 by Leopold Gmelin.

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<span class="mw-page-title-main">Cyanohydrin</span> Functional group in organic chemistry

In organic chemistry, a cyanohydrin or hydroxynitrile is a functional group found in organic compounds in which a cyano and a hydroxy group are attached to the same carbon atom. The general formula is R2C(OH)CN, where R is H, alkyl, or aryl. Cyanohydrins are industrially important precursors to carboxylic acids and some amino acids. Cyanohydrins can be formed by the cyanohydrin reaction, which involves treating a ketone or an aldehyde with hydrogen cyanide (HCN) in the presence of excess amounts of sodium cyanide (NaCN) as a catalyst:

In organic chemistry, a nitrile is any organic compound that has a −C≡N functional group. The prefix cyano- is used interchangeably with the term nitrile in industrial literature. Nitriles are found in many useful compounds, including methyl cyanoacrylate, used in super glue, and nitrile rubber, a nitrile-containing polymer used in latex-free laboratory and medical gloves. Nitrile rubber is also widely used as automotive and other seals since it is resistant to fuels and oils. Organic compounds containing multiple nitrile groups are known as cyanocarbons.

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

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 jewellery for chemical gilding and buffing.

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

Zinc chloride is the name of inorganic chemical compounds with the formula ZnCl2 and its hydrates. Zinc chlorides, of which nine crystalline forms are known, are colorless or white, and are highly soluble in water. This salt is hygroscopic and even deliquescent. Zinc chloride finds wide application in textile processing, metallurgical fluxes, and chemical synthesis. No mineral with this chemical composition is known aside from the very rare mineral simonkolleite, Zn5(OH)8Cl2·H2O.

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

Aluminium chloride, also known as aluminium trichloride, is an inorganic compound with the formula AlCl3. It forms hexahydrate with the formula [Al(H2O)6]Cl3, containing six water molecules of hydration. Both are colourless crystals, but samples are often contaminated with iron(III) chloride, giving a yellow color.

<span class="mw-page-title-main">Mercury(II) cyanide</span> Chemical compound

Mercury(II) cyanide, also known as mercuric cyanide, is a compound of mercury. It is an odorless, toxic white powder. It is highly soluble in polar solvents such as water, alcohol, and ammonia; slightly soluble in ether; and insoluble in benzene and other hydrophobic solvents.

The Gattermann reaction, (also known as the Gattermann formylation and the Gattermann salicylaldehyde synthesis) is a chemical reaction in which aromatic compounds are formylated by a mixture of hydrogen cyanide (HCN) and hydrogen chloride (HCl) in the presence of a Lewis acid catalyst such as AlCl3. It is named for the German chemist Ludwig Gattermann and is similar to the Friedel–Crafts reaction.

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

Sodium thiocyanate (sometimes called sodium sulphocyanide) is the chemical compound with the formula NaSCN. This colorless deliquescent salt is one of the main sources of the thiocyanate anion. As such, it is used as a precursor for the synthesis of pharmaceuticals and other specialty chemicals. Thiocyanate salts are typically prepared by the reaction of cyanide with elemental sulfur:

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

Cadmium cyanide is an inorganic compound with the formula Cd(CN)2. It is a white crystalline compound that is used in electroplating. It is very toxic, along with other cadmium and cyanide compounds.

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

Ammonium cyanide is an unstable inorganic compound with the formula NH4CN.

In nitrile reduction a nitrile is reduced to either an amine or an aldehyde with a suitable chemical reagent.

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

Lithium cyanide is an inorganic compound with the chemical formula LiCN. It is a toxic, white colored, hygroscopic, water-soluble salt that finds only niche uses.

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

Potassium tetracyanonickelate is the inorganic compound with the formula K2Ni(CN)4. It is usually encountered as the monohydrate but the anhydous salt is also known. Both are yellow, water-soluble, diamagnetic solids. The salt consists of potassium ions and the tetracyanonickelate coordination complex, which is square planar.

References

  1. ↑ Zinc cyanide toxicity
  2. ↑ "ZINC cyanide". pubchem.ncbi.nlm.nih.gov.
  3. "ZINC CYANIDE | CAMEO Chemicals | NOAA". cameochemicals.noaa.gov.
  4. ↑ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN   978-0-08-037941-8.
  5. 1 2 F. Wagenknecht; R. Juza (1963). "Zinc cyanide". In G. Brauer (ed.). Handbook of Preparative Inorganic Chemistry, 2nd Ed. Vol. 2. NY, NY: Academic Press. p. 1087.
  6. 1 2 Ernst Gail, Stephen Gos, Rupprecht Kulzer, Jürgen Lorösch, Andreas Rubo and Manfred Sauer "Cyano Compounds, Inorganic" Ullmann's Encyclopedia of Industrial Chemistry Wiley-VCH, Weinheim, 2004. doi : 10.1002/14356007.a08_159.pub2
  7. ↑ Adams, Roger (1957). Organic Reactions, Volume 9. New York: John Wiley & Sons, Inc. pp. 53–54. ISBN   9780471007265 . Retrieved 18 July 2014.
  8. ↑ Adams R., Levine I. (1923). "Simplification of the Gattermann Synthesis of Hydroxy Aldehydes". J. Am. Chem. Soc. 45 (10): 2373–77. doi:10.1021/ja01663a020.Fuson R. C., Horning E. C., Rowland S. P., Ward M. L. (1955). "Mesitaldehyde". Organic Syntheses . doi:10.15227/orgsyn.023.0057.{{cite journal}}: CS1 maint: multiple names: authors list (link); Collective Volume, vol. 3, p. 549
  9. ↑ Rasmussen J. K., Heilmann S. M. (1990). "In situ Cyanosilylation of Carbonyl Compounds: O-Trimethylsilyl-4-Methoxymandelonitrile". Organic Syntheses . doi:10.15227/orgsyn.062.0196.; Collective Volume, vol. 7, p. 521


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