C.I. Acid Black 84; Acid Black 84; 2-naphthalenesulfonate, 3-[(E)-2-(5-nitro-2-olato-3-sulfonatophenyl)diazenyl]-4-olato-6-[(sulfonatomethyl)amino]- 3-[(E)-2-(5-nitro-2-olato-3-sulfonatophenyl)diazenyl]-4-olato-7-[(sulfonatomethyl)amino]-2-naphthalenesulfonate, chromium sodium salt (1:1:1:6)