| 423 / | HD | CHEMISTRY OF INORGANIC COMPOUNDS |
| 351 | DF | NITROGEN OR COMPOUND THEREOF (EXCEPT AMMONIUM SALT OF NON-NITROGEN ACID) {5} |
| 352 | | .~ Ammonia or ammonium hydroxide {6} |
| 353 | DF | .~.~> From nitride of metal or silicon |
| 354 | DF | .~.~> And producing inorganic carbon and nitrogen containing compound |
| 355 | DF | .~.~> By hydrolyzing inorganic carbon and nitrogen containing compound |
| 356 | DF | .~.~> From ammonium compound {1} |
| 358 | DF | .~.~> From organic material containing nitrogen |
| 359 | DF | .~.~> From elemental hydrogen and nitrogen {3} |