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 such ligands are bound to the iron. As such the complex is chiral
Naphthol Green B is used in histology to stain collagen. 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.