63494-80-4 Benzoic acid, 3-((4-hydroxy-3-sulfophenyl)(4-oxo-3-sulfo-2,5-cyclohexadien-1-ylidene)methyl)-, calcium salt (1:1) Calcium hydrogen 3-((4-hydroxy-3-sulphonatophenyl)(4-oxo-3-sulphonato-2,5-cyclohexadien-1-ylidene)methyl)benzoate EINECS 264-272-4