| 568 / | HD | ORGANIC COMPOUNDS -- PART OF THE CLASS 532-570 SERIES |
| * | DD | ORGANIC COMPOUNDS (Class 532, Subclass 1) {4} |
| 18 | DF | .~ SULFUR CONTAINING {9} |
| 21 | DF | .~.~ Sulfur bonded directly to sulfur (e.g., disulfides, etc.) {4} |
| 22 | | .~.~.~ Oxygen containing {1} |
| 23 | DF | .~.~.~.~> Sulfur or oxygen bonded directly to a ring |