| 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} |
| 924 | DF | .~.~ Nitro containing (including aci forms) {6} |
| 927 | DF | .~.~.~ Benzene ring containing {4} |
| 928 | | .~.~.~.~ Plural rings containing {2} |
| 929 | DF | .~.~.~.~.~> Polycyclo ring system {1} |
| 931 | DF | .~.~.~.~.~> Polynitro |