Purity, % :97.0-102.0
pH : 5.0-7.5
Drying loss, % :≤5.0
Water-soluble substances, % :≤0.2
Chloride, % :≤0.030
Heavy metal, % :≤0.001
Residue on ignition, % :≤0.2
As, % :≤0.0002
Appearance: White or offwhite powder. Odorless.
Particle size: >50.0% through #9 sieve; <5% through #7 sieve.
Solubility: Insoluble in water, dilute acid and most organic solvents. Slightly soluble in NaOH solution (1:20).