Chemistry informtion about Acid Blue 9 (CAS NO.2650-18-2) is:
IUPAC Name: Diazanium 2-[[4-[Ethyl-[(3-Sulfonatophenyl)Methyl]Amino]Phenyl]-[4-[Ethyl-[(3-Sulfonatophenyl)Methyl]Azaniumylidene]Cyclohexa-2,5-Dien-1-Ylidene]Methyl]Benzenesulfonate
Synonyms: Acilan Turquoise Blue AE ; Aizen Brilliant Blue FCF ; Alphazurine (indicator) ; Alphazurine FG ; Brilliant Blue ; Brilliant Blue Lake ; Bucacid Azure Blue ; Ammonium, ethyl(4-(p-(ethyl(m-sulfobenzyl)amino)-alpha-(o-sulfophenyl)benzylidene)-2,5-cyclohexadien-1-ylidene)(m-sulfobenzyl)-, hydroxide, inner salt, diammonium salt ; Diammonio(ethyl)(4-((4-(ethyl(3-sulphonatobenzyl)amino)phenyl)(2-sulphonatophenyl)methylene)cyclohexa-2,5-dien-1-ylidene)(3-sulphonatobenzyl)ammonium
Molecular Formula: C₃₇H₃₄N₂Na₂O₉S₃
Molecular Weight: 792.85
EINECS: 223-339-8
Melting Point: 283 °C (dec.)(lit.)
Following is the molecular structure of C.I. Acid Blue 9 (CAS NO.2650-18-2) is:

 Acid Blue 9 (CAS NO.2650-18-2) is also used in soaps, shampoos, and other hygiene and cosmetics applications. In soil science, Brilliant Blue is applied in tracing studies to visualize infiltration and water distribution in the soil. It is used as the stain in Listerine's Agent Cool Blue mouthwash. A research study at the University of Rochester Medical Centre, New York, are investigating Acid Blue 9 efficacy in treating spinal cord injuries. Tests in rats have shown that IV administration of the dye shortly after spinal trauma has the effect of blocking the natural release of a chemical (adenosine triphosphate) that causes damage to healthy cells surrounding a spinal lesion. Research continues into safety and the effective administration to humans, with one potential barrier being that the treatment has the effect of temporarily turning the skin bright blue.

Safty information about Acid Blue 9 (CAS NO.2650-18-2) is:
WGK Germany: 3
RTECS: BQ4725000

 Acid Blue 9 (CAS NO.2650-18-2) is a blue powder. It may exist as disodium, diammonium or monoammonium-monosodium salt. It is a colorant for foods and other substances to induce a color change. It is denoted by E number E133 and has a color index of 42090. It has the appearance of a reddish-blue powder. It is soluble in water, and the solution has a maximum absorption at about 628 nanometer. Acid Blue 9 has previously been banned in Austria, Belgium, Denmark, France, Germany, Greece, Italy, Norway, Spain, Sweden, and Switzerland among others but has been certified as a safe food additive in the EU and is today unbanned in most of the countries. It has the capacity for inducing an allergic reaction in individuals with pre-existing moderate asthma. In the United States production exceeds 1 million pounds annually, and daily consumption is around 16 mg per person.It is one of the colorants that the Hyperactive Children's Support Group and the Feingold Association recommends to be eliminated from the diet of children. After extensive testing, the National Institutes of Health concluded that color additives do not cause hyperactivity.