The molecule is an organic sodium salt that is the disodium salt of 2-amino-5-[(4-amino-3-sulfophenyl)(4-imino-3-sulfocyclohexa-2,5-dien-1-ylidene)methyl]-3-methylbenzene-1-sulfonic acid. It is used in the Van Gieson method in conjunction with picric acid to demonstrate collagen fibres red, and in Masson's trichrome to colour smooth muscle in contrast to collagen. It has a role as a histological dye. It contains an acid fuchsin(2-).
disodium;6-azaniumylidene-3-[bis(4-amino-3-sulfonatophenyl)methylidene]-5-methylcyclohexa-1,4-diene-1-sulfonate