Aluminium, N-[4-[[4-(diethylamino)phenyl](5-hydroxy-2,4-disulfophenyl)methylene]-2,5-cyclohexadien-1-ylidene]-N-ethylethanaminium hydroxide inner salt complexes

colourful green light blue. Soluble in water for blue, slightly soluble in ethanol for green light blue. The strong sulfuric acid for brown-olive yellow, yellow for deep diluted, and then to green. Dyes to join sodium hydroxide solution of the same color, heat into deep purple. And C.I. Acid blue 3?the same chemical structure, different salt ions.