| 568 / | HD | ORGANIC COMPOUNDS -- PART OF THE CLASS 532-570 SERIES | 
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| * | 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} | 
| 648 |  | .~.~.~.~.~ Polyoxy {3} | 
| 649 | DF | .~.~.~.~.~.~> Halogen containing | 
| 650 | DF | .~.~.~.~.~.~> Hydroxy bonded directly to the benzene ring (H of -OH may be replaced by a Group IA or IIA light metal) {2} | 
| 654 | DF | .~.~.~.~.~.~> Acyclic carbon to carbon unsaturation containing |