| 546 / | HD | ORGANIC COMPOUNDS -- PART OF THE CLASS 532-570 SERIES |
| * | DD | ORGANIC COMPOUNDS (Class 532, Subclass 1) {1} |
| * | DD | .~ HETEROCYCLIC CARBON COMPOUNDS CONTAINING A HETERO RING HAVING CHALCOGEN (I.E., OXYGEN, SULFUR, SELENIUM, OR TELLURIUM) OR NITROGEN AS THE ONLY RING HETERO ATOMS (Class 540, subclass 1) {1} |
| 1 | DF | .~.~ Hetero ring is six-membered consisting of one nitrogen and five carbons {24} |
| 2 | DF | .~.~.~ Heavy metal or aluminum containing {8} |
| 3 | | .~.~.~.~ Arsenic containing |