| 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} |
| 81 | DF | .~.~ Germanium, tin, or lead containing (Ge, Sn, or Pb) {6} |
| 87 | | .~.~.~ Carbon bonded directly to the metal {2} |
| 88 | DF | .~.~.~.~> Chalcogen bonded directly to the metal {2} |
| 95 | DF | .~.~.~.~> The compound consists of the metal, carbon and hydrogen or the metal, carbon, hydrogen and halogen (e.g., tetraalkylleads, etc.) {6} |