Expl. lim. 8 %± , 65 °F
Total impurities insoluble matter, passes filter test
Ign. residue  ≤ 0.02 % (as SO₄)
Loss ≤ 0.5 % loss on drying, 110 °C
pH = 1.0-2.0 (25 °C, 1 M in H₂O)
pK_a  (1) = 3.13, pK_a (2) = 4.76, pK_a (3) = 6.4
mp = 153-159 °C(lit.)
Solubility H₂O : 1 M at 20 °C, clear, colorless
Anion traces :
  chloride (Cl^-) : ≤ 0.001 %
  oxalate (C₂O₄^2-) : ≤ 0.003 %
  phosphate (PO₄^-) : ≤ 0.001 %
  sulfate (SO₄^2-) : ≤ 0.002 %
Cation traces :
  Fe : ≤ 3 mg/kg
  Pb : ≤ 2 mg/kg