| 204 / | HD | CHEMISTRY: ELECTRICAL AND WAVE ENERGY |
| * | DD | PROCESSES AND PRODUCTS {7} |
| 157.15 | DF | .~ Processes of treating materials by wave energy {6} |
| 157.6 | DF | .~.~ Process or preparing desired organic product containing at least one atom other than carbon and hydrogen {16} |
| 157.76 | | .~.~.~ Sulfur product produced {3} |
| 157.77 | DF | .~.~.~.~> Nitrogen containing |
| 157.78 | DF | .~.~.~.~> Oxygen containing {1} |
| 157.8 | DF | .~.~.~.~> Halogen containing |