Synonyms: calcium 4-[(2,4-dichloro-3-methyl-6-sulphonatophenyl)azo]-3-hydroxy-2-naphthoate;4-[(2,4-Dichloro-3-methyl-6-sulfophenyl)azo]-3-hydroxy-2-naphthalenecarboxylic acid calcium salt;2-Naphthalenecarboxylic acid, 4-((2,4-dichloro-3-methyl-6-sulfophenyl)azo)-3-hydroxy-, calcium salt (1:1);2-Naphthalenecarboxylic acid, 4-(2-(2,4-dichloro-3-methyl-6-sulfophenyl)diazenyl)-3-hydroxy-, calcium salt (1:1);4-((2,4-Dichloro-3-methyl-6-sulfophenyl)azo)-3-hydroxy-2-naphthalenecarboxylic acid, calcium salt (1:1);Einecs 267-724-9