Silver acetylide

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Silver acetylide
Names
IUPAC name
Silver acetylide
Other names
Argentous acetylide
Argentous carbide
Argentous dicarbide
Argentous ethynediide
Argentous percarbide
Silver carbide
Silver dicarbide
Silver percarbide
Silver(I) acetylide
Silver(I) ethynediide
Properties
Ag2C2
Molar mass 239.758 g·mol
Appearance White or gray precipitate
Odor Odorless
Density 4.47 g/cm3
Melting point 120 °C (248 °F; 393 K) (explosive decomposition)
Boiling point Decomposition
Insoluble
Solubility Reacts with acids
Insoluble in solvents
Vapor pressure ~0 mmHg
Thermochemistry
357.6±5.0 kJ/mol[1]
Hazards
Safety data sheet None
Flash point 77 °C (171 °F; 350 K)
Related compounds
Related compounds
Copper(I) acetylide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Silver acetylide is an inorganic chemical compound with the formula Ag2C2, a metal acetylide.

Properties

Chemical

Pure silver acetylide is a heat- and shock-sensitive primary explosive. Silver acetylide decompose through the reaction:

Ag2C2 (s) → 2 Ag (s) + 2 C (s)

Like other metal acetylides, it reacts with acids to release acetylene gas.

Physical

Silver acetylide is a white to gray solid, odorless and insoluble in water and solvents.

Explosive

Silver acetylide is highly sensitive to heat and mechanical shock when dry, though less so when wet.[2]

The detonation velocity of the silver acetylide-silver nitrate double salt is 1980 m/s, while that of pure silver acetylide is 1200 m/s.[3]

Availability

Silver acetylide is not sold due to its instability and has to be made in situ.

Preparation

Silver acetylide can be produced by passing acetylene gas through a solution of silver nitrate in aq. ammonia:[4][5]

2 AgNO3 (aq) + C2H2 (g) → Ag2C2 (s) + 2 HNO3 (aq)

The reaction product is a greyish to white precipitate, depending on the purity of acetylene.

If the reaction is done in acidic or neutral solution, the product will be a double salt of acetylide and silver nitrate.

Projects

  • Pyrotechnic demonstration

Handling

Safety

Silver acetylide is stable when wet, but the dry pure form is highly sensitive to shock and heat, and will explode if disturbed.

Storage

Should not be stored and used up as soon as possible.

Disposal

Can be safely neutralized when wet, by carefully adding and acid, like hydrochloric acid. This produces silver chloride and acetylene gas, so this process must be done outside.

References

  1. Finch, Arthur; Gardner, Peter J.; Head, Arthur J.; Majdi, Hassan S. (1991). "The standard enthalpy of formation of silver acetylide". Thermochimica Acta. 180: 325–330
  2. https://www.youtube.com/watch?v=Pc4jnqwOSPE
  3. Matyáš, Robert; Pachman, Jiří (2013). Primary Explosives. Berlin, Heidelberg: Springer Berlin Heidelberg
  4. https://woelen.homescience.net/science/chem/exps/silveracetylide/index.html
  5. https://www.youtube.com/watch?v=F_TIVJS-lFc

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