Silver cyanide

Summary

Silver cyanide
Silver cyanide
Ag C/N
Names
IUPAC name
Silver cyanide
Other names
Argentous cyanide
Identifiers
  • 506-64-9 checkY
3D model (JSmol)
  • Interactive image
ChemSpider
  • 10043 checkY
ECHA InfoCard 100.007.317 Edit this at Wikidata
EC Number
  • 208-048-6
  • 10475
RTECS number
  • VW3850000
UNII
  • 33RV6XQ01M checkY
UN number 1684
  • DTXSID9024306 Edit this at Wikidata
  • InChI=1S/CN.Ag/c1-2;/q-1;+1 checkY
    Key: LFAGQMCIGQNPJG-UHFFFAOYSA-N checkY
  • InChI=1/CN.Ag/c1-2;/q-1;+1
    Key: LFAGQMCIGQNPJG-UHFFFAOYAM
  • [C-]#N.[Ag+]
Properties
AgCN
Molar mass 133.8856 g/mol
Appearance colorless, gray (impure) crystals
Odor odorless
Density 3.943 g/cm3
Melting point 335 °C (635 °F; 608 K) (decomposes)
0.000023 g/100 mL (20 °C)
5.97×10−17[1]
Solubility soluble in concentrated ammonia, boiling nitric acid, ammonium hydroxide, KCN
insoluble in alcohol, dilute acid
−43.2·10−6 cm3/mol
1.685
Structure
hexagonal
linear
Thermochemistry
84 J·mol−1·K−1[2]
146 kJ·mol−1[2]
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
toxic
GHS labelling:
GHS05: CorrosiveGHS06: ToxicGHS09: Environmental hazard
Danger
H290, H300, H310, H315, H318, H330, H410
P234, P260, P262, P264, P270, P271, P273, P280, P284, P301+P310, P302+P350, P302+P352, P304+P340, P305+P351+P338, P310, P320, P321, P322, P330, P332+P313, P361, P362, P363, P390, P391, P403+P233, P404, P405, P501
NFPA 704 (fire diamond)
3
1
1
Flash point 320 °C (608 °F; 593 K)
Lethal dose or concentration (LD, LC):
123 mg/kg (oral, rat)
Related compounds
Other anions
AgCl
Other cations
NaCN
Copper(I) cyanide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Silver cyanide is the chemical compound with the formula AgCN. It is a white solid that precipitated upon treatment of solutions containing Ag+ with cyanide, which is used in some schemes to recover silver from solution. Silver cyanide is used in silver-plating.

Structure

The structure of silver cyanide consists of -[Ag-CN]- chains in which the linear two-coordinate Ag+ ions are bridged by the cyanide ions,[3] typical of silver(I) and other d10 ions. This is the same binding mode as seen in the more famous case of Prussian blue. These chains then pack hexagonally with adjacent chains offset by +/- 1/3 of the c lattice parameter. This is the same as the structure adopted by the high temperature polymorph of copper(I) cyanide. The silver to carbon and silver to nitrogen bond lengths in AgCN are both ~2.09 Å[4] and the cyanide groups show head-to-tail disorder.[5]

Reactions

AgCN precipitates upon the addition of sodium cyanide to a solution containing Ag+. The precipitate dissolves upon the addition of further amounts of cyanide to form linear [Ag(CN)2](aq) and [Ag(CN)3]2−(aq) on the addition of further cyanide. Silver cyanide is also soluble in solutions containing other ligands such as ammonia or tertiary phosphines.

Silver cyanides form structurally complex materials upon reaction with other anions.[6] Some silver cyanides are luminescent.[7]

Uses

Both AgCN and KAg(CN)2 have been used in silver-plating solutions since at least 1840 when the Elkington brothers patented their recipe for a silver-plating solution. A typical, traditional silver-plating solution would contain 15-40 g·L−1 KAg(CN)2 , 12-120 g·L−1 KCN and 15 g·L−1 K2CO3.[8]

See also

References

  1. ^ John Rumble (June 18, 2018). CRC Handbook of Chemistry and Physics (99 ed.). CRC Press. pp. 5–189. ISBN 1138561630.
  2. ^ a b Zumdahl, Steven S. (2009). Chemical Principles 6th Ed. Houghton Mifflin Company. p. A23. ISBN 978-0-618-94690-7.
  3. ^ Bowmaker, Graham A.; Kennedy, Brendan J.; Reid, Jason C. (1998). "Crystal Structures of AuCN and AgCN and Vibrational Spectroscopic Studies of AuCN, AgCN, and CuCN". Inorg. Chem. 37 (16): 3968–3974. doi:10.1021/ic9714697.
  4. ^ Hibble, S. J.; Cheyne, S. M.; Hannon, A. C.; Eversfield, S. G. (2002). "Beyond Bragg scattering: the structure of AgCN determined from total neutron diffraction". Inorganic Chemistry. 41: 1042–1044. doi:10.1021/ic015610u.
  5. ^ Bryce, David L.; Wasylishen, Roderick E. (2002). "Insight into the Structure of Silver Cyanide from 13C and 15N Solid-State NMR Spectroscopy". Inorganic Chemistry. 41 (16): 4131–4138. doi:10.1021/ic0201553. ISSN 0020-1669. PMID 12160400.
  6. ^ Urban, Victoria; Pretsch, Thorsten; Hartl, Hans (2005-04-29). "From AgCN Chains to a Fivefold Helix and a Fishnet-Shaped Framework Structure". Angewandte Chemie International Edition. 44 (18): 2794–2797. doi:10.1002/anie.200462793. ISSN 1433-7851. PMID 15830404.
  7. ^ Omary, Mohammad A.; Webb, Thomas R.; Assefa, Zerihun; Shankle, George E.; Patterson, Howard H. (1998). "Crystal Structure, Electronic Structure, and Temperature-Dependent Raman Spectra of Tl[Ag(CN)2]: Evidence for Ligand-Unsupported Argentophilic Interactions". Inorganic Chemistry. 37 (6): 1380–1386. doi:10.1021/ic970694l. ISSN 0020-1669. PMID 11670349.
  8. ^ Blair, Alan (2000). "Silver plating". Metal Finishing. 98 (1): 298–303. doi:10.1016/S0026-0576(00)80339-6.