| 423 / | HD | CHEMISTRY OF INORGANIC COMPOUNDS |
| 511 | DF | SULFUR OR COMPOUND THEREOF {4} |
| 512.1 | DF | .~ Oxygen containing {11} |
| 544 | DF | .~.~ Sulfate {7} |
| 551 | | .~.~.~ Alkali metal containing (Li, Na, K, Rb, or Cs) {2} |
| 552 | DF | .~.~.~.~> Utilizing chloride as reactant |
| 553 | DF | .~.~.~.~> Dehydrating |