| 423 / | HD | CHEMISTRY OF INORGANIC COMPOUNDS |
| 324 | DF | SILICON OR COMPOUND THEREOF {4} |
| 325 | DF | .~ Oxygen containing {2} |
| 335 | | .~.~ Silica {5} |
| 336 | DF | .~.~.~> By hydrolyzing vapor phase silicon compound |
| 337 | DF | .~.~.~> By oxidizing volatile silicon compound (e.g., combustion, etc.) |
| 338 | DF | .~.~.~> By gelling |
| 339 | DF | .~.~.~> By precipitating |
| 340 | DF | .~.~.~> By purifying sand |