| 556 / | HD | ORGANIC COMPOUNDS -- PART OF THE CLASS 532-570 SERIES |
| * | DD | ORGANIC COMPOUNDS (Class 532, Subclass 1) {3} |
| 400 | DF | .~ SILICON CONTAINING {19} |
| 431 | DF | .~.~ Plural silicons bonded directly to the same carbon or attached by a chain consisting of carbons, which carbons may be part of a ring {3} |
| 434 | | .~.~.~ Two silicons bonded directly to the same oxygen |