Chromate,bis[4-[[3-[(5-chloro-2-hydroxyphenyl)azo]-2,4-dihydroxyphenyl]azo]-3-hydroxy-7-nitro-1-naphthalenesulfonato]-,disodium hydrogen

4-Amino-3-hydroxy-7-nitronaphthalene-1-sulfonic acid diazo, in alkaline conditions Coupled with resorcinol, 2-Amino-4-chlorophenol diazo, in alkaline conditions and formation of single accidentally coupled nitrogen compounds, then with formic acid chromium common heating, in 100 ℃ to keep four hours, make its formed chromium complex.

black.