Calcium nitrite is colorless or yellowish crystal,deliquescent, easily soluble in water and slightly soluble in ethanol. This product is widely used in reinforced concrete engineering as cement hardening accelerator and antifreeze and rust inhibitor. When 2% calcium nitrite solution is added to the concrete, the service life of the reinforced concrete building structure can be increased by 15 ~ 20 years. Calcium nitrite solution can also be used as corrosion inhibitor in pharmaceutical industry, organic synthesis and lubricating oil.