| 556 / | HD | ORGANIC COMPOUNDS -- PART OF THE CLASS 532-570 SERIES |
| * | DD | ORGANIC COMPOUNDS (Class 532, Subclass 1) {3} |
| 1 | DF | .~ HEAVY METAL CONTAINING (e.g., Ga, In or T1, etc.) {19} |
| 9 | | .~.~ Silicon containing {3} |
| 10 | DF | .~.~.~> Silicon and heavy metal bonded directly to the same chalcogen |
| 11 | DF | .~.~.~> Heavy metal bonded directly to unsaturated five-membered carbocyclic ring |
| 12 | DF | .~.~.~> At least three carbons bonded directly to silicon |