Sodium cyanide, NacN, is a cyanide salt that is a white, deliquescence, crystalline powder and is soluble in water. The specific gravity is 1.6, which is heavier than water. Sodium cyanide is toxic by inhalation and ingestion, with a TLV of 4.7 ppm and 5 mg/m^3 of air. The target organs are the cardiovascular system, central nervous system, kidneys, liver and skin. Reactions with acids can release flammable and toxic hydrogen cyanide gas. Cyanides are incompatible with all acids. The four-digit UN identification number is 1689.