Sodium bicarbonate is white crystal or opaque monoclinal fine crystal. The proportion of 2.15. Odorless, non-toxic, salty, soluble in water, slightly soluble in ethanol. Soluble in 10 parts water at 25℃, soluble in 12 parts water at about 18℃. Its aqueous solution was slightly alkaline due to hydrolysis, stable in normal temperature, easy to decompose under heat, gradually decomposed above 50℃, completely lost carbon dioxide at 270℃, no change in dry air, slow delirious in humid air.