Dark red flakes for preservation, coloring, pharmaceuticals and catalysts Chromic Acid (1) CrO3 ω/% ≥99.8 (2) So42-ω/%≤ 0.05 (3) Insoluble ω/%≤ 0.01 (4) Na ω/%≤ 0.04 (5) Turbidity NTU≤ 5.0