4,5-Dihydroxy-3-[(2-hydroxy-5-sulfophenyl)azo]-2,7-naphthalenedisulfonic acid trisodium salt; C.I.Mordant Blue 31; Chrome Blue K; 2,7-Naphthalenedisulfonicacid, 4,5-dihydroxy-3-[2-(2-hydroxy-5-sulfophenyl)diazenyl]-, sodium salt (1:3); Chrome fast navy blue R; 7-(2-Hydroxy-5-sulfophenylazo)-1,8-dihydroxynaphthalene-3,6-disulfonicacid
