Definition and Usage of Silver cyanide
Silver cyanide is the chemical compound with the formula AgCN. This white solid is formed by treating Ag+ containing solutions with cyanide. This precipitation step is used in some schemes to recover silver from solution. Silver cyanide is used in silver plating.
Its structure consists of -[Ag-CN] chains, in which linear bi-coordinated Ag + ions specific to silver (I) and other d 10 ions are bridged with cyanide ions. (It is the same binding mode seen in the more famous example of the Prussian blue.) These chains are then packed into hexagons with +/- 1/3 of the lattice parameter “c” with adjacent chains. This is the same structure adopted by the high temperature polymorph of copper(I) cyanide. The silver-carbon and silver-nitrogen bond lengths in AgCN are both ~2.09 Å and the cyanide groups show head-to-tail disorder.
Silver cyanide is the general name of hydrocyanic acid and metal salts derived from this acid.
All of them are severely poisonous. The most important are sodium cyanide and potassium cyanide. They are obtained by passing a mixture of ammonia (NH3) and CO gases over heated dry carbons in industry. HCN (Hydrocyanic acid) is a very volatile liquid with the smell of bitter almonds. It boils at 28 degrees Celsius. Its solution in water is very weak acid. Cyanide and its compounds can be produced by chemical means, as well as by some plants and animals. There are many plants, bacteria, and insects that naturally produce cyanide. Cherries, almonds, apricots, peaches, plums, beans, potatoes, radishes, cabbage, turnips, broccoli and corn naturally produce cyanide compounds.
- Many types of cyanide are consumed in different industries. A large part of the produced HCN is used in the production of chemicals, and the remaining part is used in the production of NaCN.
- Both AgCN and KAg(CN)2 have been used in silver plating solutions since at least 1840, when the Elkington brothers patented a silver plating solution for their recipe.