Acid green 5 is an organic sodium salt having 3-[(ethyl{4-[(4-{ethyl[(3-sulfonatophenyl)methyl]amino}phenyl)(4-sulfonatophenyl)methylidene]cyclohexa-2,5-dien-1-ylidene}azaniumyl)methyl]benzene-1-sulfonate as the counterion. It is the standard dye in North American for staining collagen and is also used extensively in plant histology. It has a role as a histological dye. It contains an acid green 5(2-).
