| 534 / | HD | ORGANIC COMPOUNDS -- PART OF THE CLASS 532-570 SERIES |
| * | DD | ORGANIC COMPOUNDS (CLASS 532, SUBCLASS 1) {8} |
| 573 | DF | .~ Azo {51} |
| 603 | DF | .~.~ Quaternary ammonium or hydrazinium attached indirectly to an azo group by nonionic bonding {4} |
| 614 | | .~.~.~ Plural azo groups attached indirectly to each other by nonionic bonding |