Mercury cyanide, or Hg(CN)2, is an odorless white powder at room temperature that is extremely poisonous if inhaled, touched or ingested. If mercury cyanide burns in a fire, toxic nitrous oxides are formed in smoke clouds. When mixed with water, mercury cyanide gradually produces the flammable gas hydrogen cyanide. Protective gear such as rubber gloves, dust masks and goggles are necessary to handle mercury cyanide.
Exposure to mercury cyanide produces symptoms of mercury poisoning and cyanide poisoning. If inhaled, rescue breathing must begin immediately, and nitrite pearls should be administered. Intravenous solutions of sodium nitrite can also be used to counteract the effects of mercury cyanide poisoning. Mercury cyanide poisoning affects kidneys, sensorimotor skills and breathing.
Physical properties of mercury cyanide include turning gray when exposed to light, dissolving 9.3 milligrams per 100 milliliters of cold water, and irritating levels of 0.02 milligrams per cubic meter of air. Acute poisoning occurs at levels between 1.2 to 8.5 milligrams per cubic meter of air.
Mercury cyanide is used in the manufacture of antiseptics, biocides, photographs and cyanogen gas, which is a toxic, colorless gas produced by oxidizing mercury cyanide. Oxygen, chlorine and nitrogen dioxide are used in the reaction. When mercury cyanide reacts with nitrogen dioxide, nitrogen oxide, water and cyanogen are produced.