The molecule is an organosulfonate oxoanion obtained by the removal of two protons from 2-amino-5-[(4-amino-3-sulfophenyl)(4-imino-3-sulfocyclohexa-2,5-dien-1-ylidene)methyl]-3-methylbenzene-1-sulfonic acid (the free acid form of the biological stain 'acid fuchsin'). It is a conjugate base of an acid fuchsin (free acid form).
6-azaniumylidene-3-[bis(4-amino-3-sulfonatophenyl)methylidene]-5-methylcyclohexa-1,4-diene-1-sulfonate