4,4'-bis[[2-hydroxy-3-[(phenylamino)carbonyl]-1-naphthyl]azo][1,1'-biphenyl]-2,2'-disulphonic disodium acid

2,2′-Disulfo-4,4,diaminobibenzene double nitriding, and 3-Hydroxy-N-phenyl-2-naphthamide?(2 Moore) coupled.

blue-ray red. Soluble in water for blue-ray red. The strong sulfuric acid to red light purple, blue light red after diluted precipitation. In water solution to join hydrochloric acid have blue red precipitate; With strong sodium hydroxide solution becomes deep red.