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).