calcium 4-[(3-chloro-2-ethyl-5-sulphonatophenyl)azo]-3-hydroxy-2-naphthoate 2-Naphthalenecarboxylic acid, 4-((3-chloro-2-ethyl-5-sulfophenyl)azo)-3-hydroxy-, calcium salt (1:1) 2-Naphthalenecarboxylic acid, 4-(2-(3-chloro-2-ethyl-5-sulfophenyl)diazenyl)-3-hydroxy-, calcium salt (1:1) 4-(3-Chloro-2-ethyl-5-sulfophenyl)azo)-3-hydroxy-2-naphthalenecarboxylic acid, calcium salt (1:1) Einecs 267-582-8 Calcium 4-[(3-chloro-2-ethyl-5-sulfonatophenyl)azo]-3-hydroxy-2-naphthoate