| 423 / | HD | CHEMISTRY OF INORGANIC COMPOUNDS |
| 351 | DF | NITROGEN OR COMPOUND THEREOF (EXCEPT AMMONIUM SALT OF NON-NITROGEN ACID) {5} |
| 406 | DF | .~ Binary compound {2} |
| 407 | ![]() | .~.~ Hydrazine or hydrazine hydrate {1} |
| 408 | DF | .~.~.~> Utilizing halogen or sulfur as reactant |