Synonyms: CI 45350 Acid yellow 73 Resorcinol phthalein Purity Limit: ≥ 99%(dye content) CAS No.: 2321-07-5 Molecular Formula: C20H12O5 Molecular Weight: 332.31 MDL No.: MFCD00005050 Appearance: Orange-red powder Storage Temperature: Store at RT Warnings: Light sensitive!