9770
In this study , Raman , infrared , UV / vis , NMR , and single crystal X - ray diffraction spectroscopies are used to elucidate the tautomeric equilibrium of azo dyes derived from 1 - phenyl - azo - 2 - naphthol ( Sudan I ) .
 Chemical: azo; Chemical: 1 - phenyl - azo - 2 - naphthol; Chemical: Sudan I
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: azo; Chemical: 1 - phenyl - azo - 2 - naphthol; Chemical: Sudan I