| 552 / | HD | ORGANIC COMPOUNDS -- PART OF THE CLASS 532-570 SERIES |
| * | DD | ORGANIC COMPOUNDS (Class 532, subclass 1) {11} |
| 101 | DF | .~ Acyclic carbon bonded directly to three benzene rings or to two benzene rings and a cyclohexadienyl ring, which acyclic carbon may not be bonded to a fourth carbon (e.g., triphenylmethane dyestuffs, etc.) {12} |
| 104 | | .~.~ Nitrogen, sulfur, phosphorus, or peroxy attached directly to the acyclic carbon by nonionic bonding |