Silver acetylide
Encyclopedia
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
. Silver acetylide is a heat- and shock-sensitive high explosive with the unusual property that on ignition it does not evolve any gas:
The detonation velocity of silver acetylide is 3460 m/s.
gas through a solution of silver nitrate
:
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.
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.
Metal acetylide
Acetylide, ethynide, dicarbide, or percarbide is the divalent anion with formula C22− or 2−. It may be regarded as the result of removing two protons from acetylene C2H2 or H-C≡C-H, the prototypical alkyne — that behaves as a weak acid.These terms are also used for any monovalent anion...
. 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
Acid
An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...
, acetylene
Acetylene
Acetylene is the chemical compound with the formula C2H2. It is a hydrocarbon and the simplest alkyne. This colorless gas is widely used as a fuel and a chemical building block. It is unstable in pure form and thus is usually handled as a solution.As an alkyne, acetylene is unsaturated because...
. 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
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
atoms linked by a triple bond
Triple bond
A triple bond in chemistry is a chemical bond between two chemical elements involving six bonding electrons instead of the usual two in a covalent single bond. The most common triple bond, that between two carbon atoms, can be found in alkynes. Other functional groups containing a triple bond are...
. The less specific alternative "silver carbide" is not used, although the analogous calcium compound CaC2 is called calcium carbide
Calcium carbide
thumb|right|Calcium carbide.Calcium carbide is a chemical compound with the chemical formula of CaC2. The pure material is colorless, however pieces of technical grade calcium carbide are grey or brown and consist of only 80-85% of CaC2 . Because of presence of PH3, NH3, and H2S it has a...
. Silver acetylide is a heat- and shock-sensitive high explosive with the unusual property that on ignition it does not evolve any gas:
- (s) → 2 Ag (s) + 2 C (s)
The detonation velocity of silver acetylide is 3460 m/s.
Synthesis
Silver acetylide can be produced by passing acetyleneAcetylene
Acetylene is the chemical compound with the formula C2H2. It is a hydrocarbon and the simplest alkyne. This colorless gas is widely used as a fuel and a chemical building block. It is unstable in pure form and thus is usually handled as a solution.As an alkyne, acetylene is unsaturated because...
gas through a solution of silver nitrate
Silver nitrate
Silver nitrate is an inorganic compound with chemical formula . This compound is a versatile precursor to many other silver compounds, such as those used in photography. It is far less sensitive to light than the halides...
:
- 2 + (g) → (s) + 2 (aq)
The reaction product is a greyish to white precipitate. This is the same synthesis from Berthelot
Marcellin Berthelot
Marcelin Pierre Eugène Berthelot was a French chemist and politician noted for the Thomsen-Berthelot principle of thermochemistry. He synthesized many organic compounds from inorganic substances and disproved the theory of vitalism. He is considered as one of the greatest chemists of all time.He...
in which he first found silver acetylide in 1866.
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.