| 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} |
| 631 | DF | .~.~.~.~.~ Plural rings containing {6} |
| 642 | DF | .~.~.~.~.~.~ Plural benzene rings bonded directly to each other {1} |
| 643 | | .~.~.~.~.~.~.~ Polyoxy |