Copper(I) cyanide
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| IUPAC name
Copper(I) cyanide
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| Other names
Cuprous cyanide, copper cyanide, cupricin
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3D model (JSmol)
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| ChemSpider | |
| ECHA InfoCard | 100.008.076 |
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PubChem CID
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CompTox Dashboard (EPA)
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| Properties | |
| CuCN | |
| Molar mass | 89.563 g/mol |
| Appearance | white to greenish powder |
| Density | 2.92 g/cm3[1] |
| Melting point | 474 °C (885 °F; 747 K) |
| negligible | |
| Solubility | insoluble in ethanol, cold dilute acids; soluble in NH4OH, KCN |
| Hazards | |
| NFPA 704 (fire diamond) | |
| Flash point | Non-flammable |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Copper(I) cyanide in an inorganic compound with the formula CuCN. This white solid occurs in two polymorphs; impure samples are often off-white. The compound is useful as a catalyst, in electroplating copper, and as a reagent in the preparation of nitriles.[2]
Structure
The compound is a coordination polymer, because that the copper(I) centres are linked by cyanide bridges. Both polymorphs contain -[Cu-CN]- chains. In high-temperature polymorph, HT-CuCN, which is isostructural with AgCN, the linear chains pack on a hexagonal lattice and adjacent chains are off set by +/- 1/3 c.[3] In the low-temperature polymorph, LT-CuCN, the chains deviate from linearity and pack into rippled layers which pack in an AB fashion with chains in adjacent layers rotated by 49 °.[4] LT-CuCN can be converted to HT-CuCN by heating to 563 K in an inert atmosphere. In both polymorphs the bridging cyanide groups show head-to-tail disorder.[5] Cuprous cyanide is commercially available and is supplied as the low-temperature polymorph. It may be prepared by reducing copper(II) sulfate with sodium cyanide, giving cyanogen gas and sodium sulfate as byproducts:[6]
- 2 CuSO4 + 4 NaCN → 2 CuCN + (CN)2 + 2 Na2SO4
This synthesis generates cyanogen, (CN)2(g), which is very toxic and does not give pure CuCN. A neater synthesis is the reduction of copper(II) sulfate with sodium bisulphite at 60 °C, followed by the addition of sodium cyanide precipitating pure LT-CuCN as a pale yellow powder. [7]
- 2 CuSO4 + NaHSO3 + H2O + 2 NaCN → 2 CuCN + 3 NaHSO4
Copper cyanide is insoluble in water but dissolves in solutions containing free CN- to form [Cu(CN)4]3-.
References
- ^ Lide, David R., ed. (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, FL: CRC Press. ISBN 0-8493-0487-3.
- ^ H. Wayne Richardson "Copper Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005. doi:10.1002/14356007.a07_567
- ^ S. J. Hibble, S. M. Cheyne, A. C. Hannon and S. G. Eversfield (2002). "CuCN: A Polymorphic Matirial. Structure of One Form from Total Neutron Diffraction". Inorg. Chem. 41: 8040–8048. doi:10.1021/ic0257569.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ S. J. Hibble, S. G. Eversfield, A. R. Cowley and A. M. Chippindale (2004). "Copper(I) Cyanide: A Simple Compound with a complicated Structure and Suprissing Room-Temperature Reactivity". Angew. Chem. Int. Ed. 43: 628–630. doi:10.1002/anie.200352844.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ S. Kroeker, R. E. Wasylishen and J. V. Hanna (1999). "The Structure of Solid Copper(I) Cyanide: A Multinuclear Magnetic and Quadrupole Resonance Study". Journal of the American Chemical Society. 121: 1582-158x. doi:10.1021/ja983253p.
- ^ J. V. Supniewski and P. L. Salzberg (1941). "Allyl Cyanide". Organic Syntheses; Collected Volumes, vol. 1, p. 46.
- ^ H. J. Barber (1942). "Cuprous Cyanide: A Note on its Preparation and Use". J. Chem. Soc.: 79.
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