| 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} |
| 591 | DF | .~.~.~ Plural oxygens bonded directly to the same carbon (e.g., acetals, ketals, orthoesters, orthocarbonates, etc.) {2} |
| 592 | | .~.~.~.~ Benzene ring containing {1} |
| 593 | DF | .~.~.~.~.~> Plural oxyalkylene groups bonded directly to each other |