Silver acetylide

Silver acetylide

Names
Preferred IUPAC name Disilver acetylide
Systematic IUPAC name Disilver(1+) ethyndiide
Other names Argentous ethyndiide Argentous percarbide Silver(1+) dicarbon Silver ethynide Silver percarbide
Identifiers
CAS Number	7659-31-6 Y
3D model (Jmol)	Interactive image
InChI InChI=1S/C2.2Ag/c1-2;;/q-2;2*+1 Key: FIDGMLJJLFFOEI-UHFFFAOYSA-N
SMILES [Ag+].[Ag+].[C-]#[C-]
Properties
Chemical formula	C2Ag2
Molar mass	239.76 g·mol−1
Appearance	gray or white solid
Melting point	120 °C (248 °F; 393 K)
Boiling point	decomposes
Solubility in water	insoluble
Hazards
Main hazards	High Explosive, Toxic
Flash point	77 °C (171 °F; 350 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y verify (what is YN ?)
Infobox references

Silver acetylide is an inorganic chemical compound with the formula Ag₂C₂, a metal acetylide. The compound can be regarded as a salt of the weak acid, acetylene. The salt's anion consists of two carbon atoms linked by a triple bond. The alternate name "silver carbide" is rarely used, although the analogous calcium compound CaC₂ is called calcium carbide.

Pure silver acetylide is a heat- and shock-sensitive high explosive with the unusual property that on ignition it does not evolve any gas:

Ag
2C
2 (s) → 2 Ag (s) + 2 C (s)

A common misconception about the "silver acetylide" used in commercial explosives is that it explodes without the evolution of gaseous products and that its chemical formula is Ag
2C
2. In reality, it is a double salt with the silver salt it was produced from, usually silver nitrate.^[1] The anion of the parent compound acts as the oxidizer in the decomposition reaction.

The detonation velocity of the mixture silver acetylide: silver nitrate is 3460 m/s.^[2] That of pure silver acetylide is 4000 m/s.

Synthesis

Silver acetylide can be produced by passing acetylene gas through a solution of silver nitrate:^[3]

2 AgNO
3 (aq) + C
2H
2 (g) → Ag
2C
2 (s) + 2 HNO
3 (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.^[4]

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.

Solubility

Silver acetylide is not soluble in water and is not appreciably soluble in any other solvent.

References