Silver acetylide
| Silver acetylide | |
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Disilver acetylide |
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Disilver(1+) ethyndiide |
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Other names
Argentous ethyndiide Argentous percarbide |
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| Identifiers | |
| CAS number | 7659-31-6 |
| Jmol-3D images | Image 1 |
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| Properties | |
| Molecular formula | C2Ag2 |
| Molar mass | 239.76 g mol−1 |
| Appearance | gray or white solid |
| Melting point |
120 °C |
| Boiling point |
decomposes |
| Solubility in water | insoluble |
| Hazards | |
| Main hazards | High Explosive, Toxic |
| Flash point | flammable |
 (verify) (what is:  / ?)Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Silver acetylide is an inorganic chemical compound with the formula Ag2C2, a metal acetylide. The name is derived from the way it is synthesized, and emphasizes that the compound can be regarded as a salt of the weak acid, acetylene. Since acetylene is called "ethyne" in the modern IUPAC nomenclature, the name "silver ethynide" would be more appropriate. In either case, the name makes it clear that the anion consists of two carbon atoms linked by a triple bond. The less specific alternative "silver carbide" is not used, although the analogous calcium compound CaC2 is called calcium carbide.
A common misconception about silver acetylide is that it explodes without the evolution of gaseous products and that its chemical formula is Ag2C2. In reality it is a double salt with the silver salt it was produced from. The anion of the parent compound acts as the oxidizer in the decomposition reaction.
The detonation velocity of silver acetylide:Silver Nitrate is 3460 m/s.[1]
[edit] Synthesis
Silver acetylide can be produced by passing acetylene gas through a solution of silver nitrate:[2]
- 2 AgNO3 (aq) + C2H2 (g) → Ag2C2 (s) + 2 HNO3 (aq)
The reaction product is a greyish to white precipitate. This is the same synthesis from Berthelot in which he first found silver acetylide in 1866.[3]
Silver acetylide can be formed on the surface of silver or high-silver alloys, e.g. in pipes used for transport of acetylene, if silver brazing was used in their joints.
[edit] Solubility
Silver acetylide is not soluble in water and there are no known solvents for it other than those that would decompose it.
[edit] References
- ^ http://www.powerlabs.org/chemlabs/acetylide.htm
- ^ G.-C. Guo, Q.-G. Wang, G.-D. Zhou, T. C. W. Mak (1998). "Synthesis and characterization of Ag2C2·2AgClO4·2H2O: a novel layer-type structure with the acetylide dianion functioning in a 6-η1,η1:η2,η2:η2,η2 bonding mode inside an octahedral silver cage". Chem. Commun. (3): 339–340. DOI:10.1039/a708439k.
- ^ M. P. Berthelot (1866). "Ueber eine neue Klasse zusammengesetzter metallhaltiger Radicale (A new class of combined metallic radicals)". Annalen der Chemie 138 (2): 245–253. DOI:10.1002/jlac.18661380215.
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