Orthogonal colorless or white crystalline. Soluble in water, soluble in methanol, ethanol-soluble, acetone, ethyl acetate almost insoluble. ether. Heating decomposition.

Analytical pure

Chemical pure

Content

≥99.5%

≥99%

water insoluble

≤0.005%

≤0.01%

Residue burned (So₄),

≤0.01%

≤0.05%

Acidity

Qualified

Qualified

Chloride

≤0.002%

≤0.005%

Kraft

≤0.005%

≤0.01%

Ca

≤0.003%

≤0.005%

Fe

≤0.0005%

≤0.001%

Heavy metals (Pb)

≤0.001%

≤0.002%