Aluminum, 4-hydroxy-3-[(4-sulfo-1-naphthalenyl)azo]-1-naphthalenesulfonic acid complex

4-Hydroxynaphthalene-1-sulfonic acid diazo, coupled with the 4-Hydroxynaphthalene-1-sulfonic acid, and then into aluminum salt deposit color.

blu-ray red. Soluble in water for blu-ray red, moderate soluble in alcohol for red, slightly soluble in acetone. The strong sulfuric acid for purple, after diluted magenta precipitation; In nitric acid solution for wine, and then into a red light yellow. The dye solution to join strong hydrochloric acid for red; Add thick sodium hydroxide solution for red light orange brown.