Copper (I) acetylide

Structural formula
General
Surname	Copper (I) acetylide
other names	Acetylene copper; Copper carbide;
Molecular formula	Cu 2 C 2
Brief description	red-brown solid (hydrate)
External identifiers / databases
PubChem	19021056
ChemSpider	14318114
Wikidata	Q414824
properties
Molar mass	151.11 g mol −1
Physical state	firmly
density	4.62 g cm −3
solubility	almost insoluble in water
safety instructions
GHS hazard labeling ; no classification available
GHS hazard labeling ; no classification available
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Copper (I) acetylide is a salt-like, organometallic compound that consists only of the elements copper and carbon . Copper acetylide occurs in two forms, which differ in the oxidation state of the copper. This article deals with the much better known copper (I) acetylide with the empirical formula Cu ₂ C ₂ . However, there is also a copper (II) acetylide (empirical formula [CuC ₂ ] _n , CAS No. 12540-13-5), which is available in polymeric form and is comparatively rarely mentioned in the literature.

presentation

Copper (I) acetylide can be prepared by introducing ethyne into an ammoniacal copper (I) salt solution (e.g. copper (I) chloride ). It is important that the solution only contains monovalent copper salts so that no copper (II) acetylide is formed, which is much more unstable. After the ethyne is passed in, copper (I) acetylide hydrate precipitates out as a fine red-brown precipitate.

{\ displaystyle \ mathrm {C_ {2} H_ {2} +2 \ CuCl + H_ {2} O \ longrightarrow Cu_ {2} C_ {2} \ cdot H_ {2} O \ downarrow \ +2 \ HCl}}

Anhydrous copper (I) acetylide can be obtained by reacting copper (I) iodide with potassium hydrogen acetylide in liquid ammonia at −70 ° C.

{\ displaystyle \ mathrm {2 \ CuI + KHC_ {2} + NH_ {3} \ longrightarrow Cu_ {2} C_ {2} + KI + NH_ {4} I}}

Properties and dangers

Copper (I) acetylide hydrate is a brown-red colored powder. It is insoluble in water, soluble in hydrochloric acid and potassium cyanide solution. When heated with hydrochloric acid, the moist, freshly prepared copper (I) acetylide hydrate breaks down into ethyne and copper (I) chloride (a little vinyl chloride is also formed ). Anhydrous copper (I) acetylide shows a considerably increased explosiveness compared to the hydrate produced from aqueous systems when it is vibrated or touched with sharp-edged objects. In the air, oxidation to copper (I) oxide, carbon and water takes place with a change in color to dark brown.

Copper acetylide forms highly explosive crystals. For parts and safety devices that come into contact with acetylene, the technical rules for acetylene systems and calcium carbide bearings (TRAC 207) stipulate that they must not contain more than 70% copper, as otherwise copper acetylide can form. When wet, copper (I) acetylide is stable and can be handled safely. When dry, however, it is extremely sensitive to impact and can be caused to explode by friction. The friction sensitivity is 0.1 N.

Copper acetylide is one of the carbides . Since the carbide ion [C≡C] ^{2− can be} formally derived from ethyne ( acetylene ), it belongs to a subgroup of carbides, namely to the acetylides .

use

As a catalyst in acetylene chemistry
In detonators to detonate main charges ( initial explosives )

Individual evidence

↑ ^a ^b ^c ^d ^e Georg Brauer (Ed.), With the collaboration of Marianne Baudler u. a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume I, Ferdinand Enke, Stuttgart 1975, ISBN 3-432-02328-6 , p. 986.
↑ This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.
^ T. Urbanski: Chemistry and Technology of Explosives. Vol. III, Pergamon Press, 1967, pp. 227-228.
↑ Technical rules for acetylene plants and calcium carbide bearings. on: Umwelt-online.de
↑ J. Köhler, R. Meyer, A. Homburg: Explosivstoffe. 10., completely revised. Edition. Wiley-VCH, Weinheim 2008, ISBN 978-3-527-32009-7 .

[brauer-1] Georg Brauer (Ed.), With the collaboration of Marianne Baudler u. a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume I, Ferdinand Enke, Stuttgart 1975, ISBN 3-432-02328-6 , p. 986.

[NV-2] This substance has either not yet been classified with regard to its hazardousness or a reliable and citable source has not yet been found.

[3] T. Urbanski: Chemistry and Technology of Explosives. Vol. III, Pergamon Press, 1967, pp. 227-228.

[TRAC_207a-4] Technical rules for acetylene plants and calcium carbide bearings. on: Umwelt-online.de

[Explosivstoffe-5] J. Köhler, R. Meyer, A. Homburg: Explosivstoffe. 10., completely revised. Edition. Wiley-VCH, Weinheim 2008, ISBN 978-3-527-32009-7 .