Chemical structure of an orange colored<unk> .<unk> s are organic compounds bearing the functional group R−N=N−R′, in which R and R′ are usually aryl. They are a commercially important family of<unk>  compounds, i.e. compounds containing the linkage C-N=N-C.<unk> s are widely used to treat textiles, leather articles, and some foods. Chemically related to<unk> s are<unk>  pigments, which are insoluble in water and other solvents.
Azo dye
Metacresol purple
Acid mantle
Bioactive glass
Coomassie brilliant blue
Super-oxidized solution
Lactophenol cotton blue
Bili light