| 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} |
| 64 | DF | .~.~ Arsenic, antimony, or bismuth containing (As, Sb, or Bi) {5} |
| 70 | | .~.~.~ Carbon bonded directly to the metal {1} |
| 71 | DF | .~.~.~.~> Chalcogen bonded directly to the metal (e.g., arsine oxides, etc.) {1} |