A blue pigment: Sodium cyanide, as well as other cyanide compound were not researched until the 18th century, since it is merely a synthesized compound. In 1704, chemists J. C. Dippel and H. Diesbach conducted an experiment in which they heated dry blood with potassium carbonate, called potash, and iron sulfate, called green vitriol. This resulted in the production of a blue pigment, which was called Berlin Blue in Germany and Prussian Blue in English after its place of discovery. Later, when a group of compounds with similar structures were discovered, the name cyanide was given. Cyanides are a group of simple compounds with the ion CN in its composition. Its name comes from Kyanos, a Greek word meaning blue. One of these was sodium cyanide. Because the blue pigment was easier and cheaper to produce than natural aquamarine, it was used widely as a blue dye for a while.

Uses in extracting gold, silver, and copper: In 1857, Michael Faraday discovered that cyanide solutions could dissolve gold in cyanide solutions in the presence of oxygen. The limiting factor was discovered to be the rate of oxygen consumption in the air during the reaction. In October 1887, John Seward MacArthur, with sponsors Robert and William Forrest, was issued a British Patent for his remarkable discovery of the "Process of obtaining gold and silver from ores." Interestingly, their discovery was made in the basement of their medical clinic. See Extracting Precious Metals From Their Ores for details of procedures.

Orica plant (9)

Hydrogen cyanide: During the Holocaust, Hitler used hydrogen cyanide to cheaply kill off many prisoners. The highly toxic gas is a product of reactions of sodium cyanide. As a result of the wall's continuous exposure to hydrogen cyanide, it is now visible as iron blue: it is the result of the accumulation of the compound in the damp condition.

Blue stains seen at the concentration camp at Stutthof (8).

Pesticide uses: In 1947, sodium cyanide was first issued by the government as a poison to control indoor pests, such as ants, bacteria, and other insects and rodents. Before 1972, sodium cyanide was used as a poison to kill predators. One particular use was the "Human Coyote Getter," which also used gunpowder. Because it caused human injuries and domestic dogs also became victims, the use of sodium cyanide in any kind of predator control was banned this year. However, once again in 1975, the use of sodium cyanide capsules and ejectors was reinstated, for reasons that it was safer than the "Human Coyote Getter." By 1987, the use of sodium cyanide in or near residential areas was strictly banned by the new regulations of the Environmental Protection Agency (EPA). Currently, the only registered use of this compound is to include it in a single dose capsule that is ejected into predators' mouth. For fear of accidental killings of endangered species, the labeling of sodium cyanide containers is enforced. It is to include passages that inform users of the restrictions of use, risk to human health, and the dangers to wildlife and the environment.

    Recent years: Since the 1980s, Australia has been a major location for producers of sodium cyanide. Here, the use of acid thiourea was no longer practiced, because it was not fit with the reaction tendencies of iron and substances in the typical Australian clay and soil.  The procedure using sodium cyanide also replaced the environmentally harmful and inefficient mercury amalgam procedure and is still used now. Nowadays, principle suppliers are the United States, the United Kingdom, and Germany. The concord with the environmental issues, the American OSHA (Occupational Safety and Health Administration) requires all businesses and research labs to report any discharge of more than one pound of sodium cyanide in the air. Other agencies such as the EPA regulate the uses of sodium cyanide as well as enforcements of handling rules.