| 568 / | HD | ORGANIC COMPOUNDS -- PART OF THE CLASS 532-570 SERIES | 
| * | DD | ORGANIC COMPOUNDS (Class 532, Subclass 1) {4} | 
| 300 | DF | .~ OXYGEN CONTAINING (E.G., PERCHLORYLBENZENE, ETC.) {11} | 
| 579 | DF | .~.~ Ethers {11} | 
| 626 | DF | .~.~.~ Benzene ring containing {7} | 
| 630 | DF | .~.~.~.~ Ether oxygen bonded directly to benzene ring {5} | 
| 655 |  | .~.~.~.~.~ Halogen containing {1} | 
| 656 | DF | .~.~.~.~.~.~> Halogen bonded directly to the benzene ring |