Apperance: Character bright blue asymmetric triclinic crystal or powder.

Nature: blue particles or light blue powder. Soluble in water, soluble in methanol, glycerol, ethanol-soluble. Slow weathering in the air, 30 ℃ lost 2 molecular crystal water, 110 ℃ lost 4 molecules of crystal water, 250 ℃ into white powder anhydrous. Soluble in water, the aqueous solution is acidic, 0. 2mol.L-1 aqueous solution pH 4.0. Non-flammable, toxic, irritating. It is decomposed by high heat to produce toxic sulfide smoke.

Use: Mainly used as textile mordant, agricultural pesticides, water fungicides, preservatives, also used for tanning, copper plating, mineral processing, etc.