Silver cyanide
Ag C/N
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Names | |
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IUPAC name
Silver cyanide
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Other names
Argentous cyanide
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Identifiers | |
3D model (
JSmol ) |
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ChemSpider | |
ECHA InfoCard
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100.007.317 |
EC Number |
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PubChem CID
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RTECS number
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UNII | |
UN number | 1684 |
CompTox Dashboard (EPA)
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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) | |
Solubility product (Ksp)
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5.97×10−17[1] |
Solubility | soluble in concentrated |
−43.2·10−6 cm3/mol | |
Refractive index (nD)
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1.685 |
Structure | |
hexagonal | |
linear | |
Thermochemistry | |
Std molar
entropy (S⦵298) |
84 J·mol−1·K−1[2] |
Std enthalpy of (ΔfH⦵298)formation |
146 kJ·mol−1[2] |
Hazards | |
Occupational safety and health (OHS/OSH): | |
Main hazards
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toxic |
GHS labelling: | |
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) | |
Flash point | 320 °C (608 °F; 593 K) |
Lethal dose or concentration (LD, LC): | |
LD50 (median dose)
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123 mg/kg (oral, rat) |
Related compounds | |
Other anions
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AgCl |
Other cations
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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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Silver cyanide is the chemical compound with the formula AgCN. It is a white salt that is 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 ~2.06 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+. On the addition of further cyanide, the precipitate dissolves to form linear [Ag(CN)2]−(aq) and [Ag(CN)3]2−(aq). 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.
Uses
"Cyanidation" is widely used in the isolation of silver from its ores. Partial purification of silver compounds is usually effected by froth flotation. The silver ion is then separated from the skimmed froth with cyanide, yielding a solution of [Ag(CN)2]−. The silver metal can then be plated out by electrolysis of such solutions.[8]
Both AgCN and
See also
References
- ISBN 978-1138561632.
- ^ ISBN 978-0-618-94690-7.
- PMID 11670511.
- PMID 11874335.
- PMID 12160400.
- PMID 15830404.
- PMID 11670349.
- ISBN 978-0471238966.
- .