The C.I. Acid Black, with the cas registry number  107 12218-96-1, has other names as Chromate(3-)(1-(3,5-dinitro-2-hydroxyphenyl)azo)-2-naphthalenolato(2-))(3-hydroxy-4-((2-hydroxy-1-naphthyl)azo)-7-nitro-1-naphthalenesulfonato(3-)), sodium dihydrogen. Its molecular formula is not specified yet. This is a kind of black powder. With the water solubility is 30g/L, the color of the aqueous solution is blue grey.

The production method of making this chemical is as follows: Firstly, prepare the material of 5-nitro-2-aminophenol, 4-nitro-2-aminophenol, 1-acetamido-7-naphthol, 2-naphthol and A(C.I.mordant Black 1); Secondly, dizotize the 5-nitro-2-aminophenol and 4-nitro-2-aminophenol, and then seperately couple with  1-acetamido-7-naphthol and 2-naphthol; Thirdly, have the complexing with A(C.I.mordant Black 1) by sodium chromium salicyloate; Finally, filter and then dry to get the products.

As to its usage, it is widely applied in many ways. It could be used in dyeing of wool, silk in faintly acid or neutral dyeing bath; It could also be used in the dyeing of nylon and vinylon in neutral dye bath and also in the direct printing of wool, silk, and nylon fabrics. When it is used for dyeing of wool and other fabric in the same dye bath, the nylon get the much darker color, the silk get much lighter, while the secondary acetate and viscose acetal fibre get a little color. Besides, it could also be used in the dyeing of leather, tussah silk, cotton or blend fabrics.