| 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} |
| 57 | | .~.~ Chromium, molybdenum, or tungsten containing (Cr, Mo, or {2} |
| 58 | DF | .~.~.~> Carbon bonded directly to the metal {1} |
| 61 | DF | .~.~.~> Containing -C(=X)X-, wherein the X's are the same or diverse chalcogens {2} |