Chemical formula Zn (CN)2
Molar mass 117,444 g/mol
Appearance Grey powder
Density 1.852 g / cm3 , solid
Melting point 800° C (1,470° F, 1,070 K)
Water solubility0,00005 g / 100 ml (20° C)
Solubility Attack for Alcalis KCN
Magnetic susceptibility -46,0x10-6 cm3/mol
In Zn (CN) 2, zinc adopts the tetrahedral coordination environment, all linked by bridging cyanide ligands. The structure consists of two "interpenetrating" structures (blue and red in the image above). These motifs are sometimes called "expanded diamondoid" structures. Some forms of SiO 2 adopt a similar structure, in which the tetrahedral centers of Si are linked by oxides. The cyanide group shows a head-to-tail disorder with any zinc atom having between one and four carbon neighbors, and the remaining nitrogen atoms. It shows one of the largest negative coefficients of thermal expansion (beating the previous record holder, zirconium tungstate).
The main application of Zn (CN) 2 is zinc plating from aqueous solutions containing additional cyanide. Zn (CN) 2 is used to introduce the formyl group into aromatic compounds in the Gatterman reaction, where it serves as a convenient, safer, and non-gaseous alternative to HCN. Because the reaction uses HCl, Zn (CN) 2 also supplies the reaction in situ with ZnCl 2, a Lewis acid catalyst. Examples of Zn (CN) 2 that are used in this way include the synthesis of 2-hydroxy-1-naphthaldehyde and mesitaldehyde.
Zn (CN) 2 is also used as a catalyst for the cyanosilylation of aldehydes and ketones.
It is one of the few substances that form soluble compounds with gold, forming a cyanide complex, and for this reason it is used in jewelry for chemical gilding and to give this metal a shine.
Typical of an inorganic polymer, Zn (CN) 2 is insoluble in most solvents. The solid is dissolved or, more precisely, degraded by aqueous solutions of basic ligands such as hydroxide, ammonia and additional cyanide to give anionic complexes.