| 423 / | HD | CHEMISTRY OF INORGANIC COMPOUNDS |
| 1 | DF | TREATING MIXTURE TO OBTAIN METAL CONTAINING COMPOUND {15} |
| 53 | DF | .~ Group VIB metal (Cr, Mo, or W) {4} |
| 55 | DF | .~.~ Forming insoluble substance in liquid {3} |
| 58 | | .~.~.~ Forming compound containing plural metals |