Zinc cyanide

Structural formula
General
Surname	Zinc cyanide
other names	Zinc cyanide; Cyan zinc; Zinc dicyanide;
Molecular formula	Zn (CN) 2
Brief description	colorless to white solid with a bitter almond odor
External identifiers / databases
EC number	209-162-9
ECHA InfoCard	100.008.331
PubChem	2734669
Wikidata	Q204713
properties
Molar mass	117.43 g mol −1
Physical state	firmly
density	1.852 g cm −3
Melting point	800 ° C (decomposition)
solubility	almost insoluble in water (5 mg l −1 at 20 ° C)
safety instructions
H and P phrases	H: 300-310-330-410
	EUH: 032
	P: 260-264-273-280-284-301 + 310
MAK	2 mg m −3
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Zinc cyanide is an inorganic chemical compound made up of zinc and cyanide .

Occurrence

Zinc cyanide is a by-product in the extraction of gold , where zinc is added to a gold cyanide solution to obtain pure gold.

Extraction and presentation

Zinc cyanide can be precipitated from a zinc sulfate or zinc chloride solution by adding a solution of potassium cyanide or sodium cyanide .

{\ displaystyle \ mathrm {ZnSO_ {4} +2 \ KCN \ longrightarrow Zn (CN) _ {2} + K_ {2} SO_ {4}}}

properties

Zinc cyanide can be obtained as a white, amorphous powder or in the form of shiny prisms, depending on how it is manufactured. It is insoluble in water and ethanol, and soluble in alkali cyanides and aqueous ammonia. In dilute acids it dissolves with evolution of hydrogen cyanide. It slowly decomposes in humid air containing carbon dioxide, especially at elevated temperatures.

Zinc cyanide has a polymeric structure in which the tetrahedrally coordinated zinc is linked by bridges made of cyanide ligands . Alternatively, the structure can also be seen as two overlapping adamantanes . The connection has one of the largest negative coefficients of linear expansion .

use

Zinc cyanide is used in electroplating for the electrolytic deposition of zinc and brass . It also serves as a catalyst in the cyanosilylation of aldehydes and ketones and for the introduction of formyl groups in organic syntheses. For example, 2-hydroxy-1-naphthaldehyde is obtained by reacting 2-naphthol , zinc cyanide and hydrogen chloride.

safety instructions

When zinc cyanide comes into contact with acids , hydrogen cyanide ( hydrogen cyanide ) is released. Contact with magnesium poses a risk of explosion.

Web links

Kosaku Masaki: Galvanic deposition of alloys from metal cyanides in cyanide solution. In: Bulletin of the Chemical Society of Japan. 7, 1932, p. 158, doi : 10.1246 / bcsj.7.158 .

Individual evidence

↑ ^a ^b ^c ^d ^e ^f ^g Entry on zinc cyanide in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .
↑ Not explicitly listed in Regulation (EC) No. 1272/2008 (CLP) , but with the indicated labeling it falls under the group entry salts of hydrogen cyanide with the exception of complex cyanides such as ferrocyanides, ferricyanides and mercuric oxycyanide and those specified elsewhere in this Annex in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
↑ Georg Brauer (Ed.), With the collaboration of Marianne Baudler a . a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume II, Ferdinand Enke, Stuttgart 1978, ISBN 3-432-87813-3 , p. 1036.
↑ JK Rasmussen, SM Heilmann: In situ Cyanosilylation of Carbonyl Compounds: O-Trimethylsilyl-4-Methoxymandelonitrile In: Organic Syntheses . 62, 1984, p. 196, doi : 10.15227 / orgsyn.062.0196 ; Coll. Vol. 7, 1990, p. 521 ( PDF ).
^ Roger Adams , I. Levine: Simplification of the Gattermann Synthesis of Hydroxy Aldehydes . In: Journal of the American Chemical Society , 1923, 45, pp. 2373-2377, doi : 10.1021 / ja01663a020 .
↑ RC Fuson, EC Horning, SP Rowland, ML Ward: Mesitaldehyde In: Organic Syntheses . 23, 1943, p. 57, doi : 10.15227 / orgsyn.023.0057 ; Coll. Vol. 3, 1955, p. 549 ( PDF ).

[GESTIS-1] ↑ ^a ^b ^c ^d ^e ^f ^g Entry on zinc cyanide in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .

[CLP_100.240.759-2] Not explicitly listed in Regulation (EC) No. 1272/2008 (CLP) , but with the indicated labeling it falls under the group entry salts of hydrogen cyanide with the exception of complex cyanides such as ferrocyanides, ferricyanides and mercuric oxycyanide and those specified elsewhere in this Annex in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .

[brauer-3] Georg Brauer (Ed.), With the collaboration of Marianne Baudler a . a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume II, Ferdinand Enke, Stuttgart 1978, ISBN 3-432-87813-3 , p. 1036.

[4] JK Rasmussen, SM Heilmann: In situ Cyanosilylation of Carbonyl Compounds: O-Trimethylsilyl-4-Methoxymandelonitrile In: Organic Syntheses . 62, 1984, p. 196, doi : 10.15227 / orgsyn.062.0196 ; Coll. Vol. 7, 1990, p. 521 ( PDF ).

[5] Roger Adams , I. Levine: Simplification of the Gattermann Synthesis of Hydroxy Aldehydes . In: Journal of the American Chemical Society , 1923, 45, pp. 2373-2377, doi : 10.1021 / ja01663a020 .

[6] RC Fuson, EC Horning, SP Rowland, ML Ward: Mesitaldehyde In: Organic Syntheses . 23, 1943, p. 57, doi : 10.15227 / orgsyn.023.0057 ; Coll. Vol. 3, 1955, p. 549 ( PDF ).