The molecule is an organosulfonate oxoanion obtained by deprotonation of the sulfonic acid groups of Sirius red F3B (acid form). It is a conjugate base of a Sirius red F3B (acid form).
4-hydroxy-7-[[5-hydroxy-7-sulfonato-6-[[2-sulfonato-4-[(4-sulfonatophenyl)diazenyl]phenyl]diazenyl]naphthalen-2-yl]carbamoylamino]-3-[[2-sulfonato-4-[(4-sulfonatophenyl)diazenyl]phenyl]diazenyl]naphthalene-2-sulfonate