| 423 / | HD | CHEMISTRY OF INORGANIC COMPOUNDS |
| 324 | DF | SILICON OR COMPOUND THEREOF {4} |
| 325 | DF | .~ Oxygen containing {2} |
| 326 | | .~.~ Metal containing (i.e., silicate) {3} |
| 327.1 | DF | .~.~.~> Aluminum containing {2} |
| 331 | DF | .~.~.~> Alkaline earth metal containing (Mg, Ca, Sr, or Ba) |
| 332 | DF | .~.~.~> Alkali metal containing (Li, Na, K, Rb, or Cs) {2} |