Properties: White orthorhombic crystallization, slight acid, easily deliquescent in the air, soluble in water very easily. Its liquor is strong acid and poisonous, which can erode glass.

Application: Mainly used as glass etching agents (together with fluohydric acid) in the production of etched glass. It also can be utilized as a chemical agent, disinfection and antiseptic agent in fermentation industry, solvent in making beryllium from beryllia and the surface treating agent of silicon steel plate. And more, it's used in ceramic, magnesium alloy, the detergent in boiler feed water system and steam-generating system, acidizing of the sandstone in oil well, and the catalyzer of alkylation isomerization.