Naphthol Green B is a coordination complex of iron that is used as a dye. The ligand is a sulfonated derivative of 1-nitroso-2-naphthol.
Naphthol Green B is the sodium salt of Naphthol Green Y (C.I. 10005). The organic ligands each bind to iron as bidentate ligands through the nitrogen and the anionic phenoxide groups. Three ligands are bound to the iron.[1]
Its absorption maximum is 714 nm in water.[2] It is water-soluble.
Naphthol Green B is used in histology to stain collagen.[3] Moreover, it is used for polychrome stains with animal tissue. For industry purposes Naphthol Green B is used for staining wool, nylon, paper, anoxidized aluminium and soap.