Sodium cyanide

Sodium cyanide is a highly toxic chemical compound, also known as sodium salt of hydrocyanic acid and cyanogran. Immediate medical attention is required in the event of cyanide poisoning, as it is quickly fatal. Like the similar potassium cyanide, NaCN has a smell like bitter almonds, but not everyone can smell it due to a genetic trait.

Sodium cyanide is used to extract gold and other precious metals from ore, and so metal mining operations consume most of the sodium cyanide production; see cyanide process for the use in gold mining. Sodium cyanide is illegally used to collect fish; see cyanide fishing. Accidents with cyanide solutions are a severe danger to aquatic ecosystems. It is often used by entomologists as a killing agent in collecting jars, as most insects succumb within seconds, minimizing damage of even the most fragile types.

Toxicity
Cyanide salts are among the most rapidly acting of all known poisons. Cyanide is a potent inhibitor of respiration, acting on mitochondrial cytochrome oxidase and hence blocking electron transport. This results in decreased oxidative metabolism and oxygen utilization. Lactic acidosis then occurs as a consequence of anaerobic metabolism. Initially, acute cyanide poisoning causes a red or ruddy complexion in the victim because the tissues are not able to use the oxygen in the blood.

The effects of sodium cyanide are similar to potassium cyanide. Once more than 100–200 mg of sodium cyanide is consumed, consciousness is lost within one minute, sometimes within 10 seconds, depending on the strength of the body's immunity and the amount of food present in the stomach. After a span of about 45 minutes, the body goes into a state of coma or deep sleep and the person may die within two hours if not treated medically. During this period, convulsions may occur. Death occurs mainly by cardiac arrest.

Source

 * Institut national de recherche et de sécurité (1997). "Cyanure de sodium. Cyanure de potassium". Fiche toxicologique n° 111, Paris:INRS, 6pp. (PDF file, in French)