| 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} |
| 583 | DF | .~.~.~ Nitrogen containing {2} |
| 584 | DF | .~.~.~.~ Ether oxygen bonded directly to benzene ring {3} |
| 588 | | .~.~.~.~.~ Halogen containing |