Zinc cyanide

• Zyanzink
• Cyanzink
• Zinkdicyanid

Colorless to white solid with bittermandelartigem odor

Fixed

1.85 g · cm -3

800 ° C ( decomposition)

Insoluble in water (5 mg · l-1 at 20 ° C)

Risk

2 mg · m-3

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Zinc cyanide is an inorganic chemical compound consisting of zinc, and cyanide.

Occurrence

Zinc cyanide is a by-product of the extraction of gold, wherein zinc is added to a Goldcyanidlösung to obtain pure gold.

Production and representation

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

Properties

Zinc cyanide is a white, amorphous powder or shiny prisms, which is insoluble in water and ethanol. It is soluble in alkali metal cyanides, and aqueous ammonia. In dilute acids it dissolves under hydrogen cyanide development. It decomposes slowly in moist air, especially at elevated temperature.

Zinc cyanide has a polymeric structure, wherein the tetrahedral zinc is connected via bridges of the cyanide ligand. Alternatively, the structure can be seen as two overlapping adamantanes. The compound has one of the most negative coefficient of linear expansion.

Use

Zinc cyanide is used in the plating industry for the electrolytic deposition of zinc or brass. It also serves as a catalyst in the Cyanosilylation of aldehydes and ketones, and the introduction of formyl groups in organic syntheses. For example, 2- hydroxy-1- naphthaldehyde produced through the reaction of 2- naphthol, zinc cyanide and hydrochloric acid.

Safety

On contact with acids of zinc cyanide Hydrogen cyanide (hydrocyanic acid) is released. In case of contact with magnesium may explode.