Assay (precipitative titration): ≥ 99.0 %
Free alkali (as KOH): ≤ 0.05 %
Free acid (as HF): ≤ 0.05 %
Chloride (Cl): ≤ 0.005 %
Hexafluorosilicate (SiF₆): ≤ 0.05 %
Sulfate (SO₄): ≤ 0.005 %
Heavy metals (as Pb): ≤ 0.001 %
Fe (Iron): ≤ 0.001 %
Na (Sodium): ≤ 0.2 %



