| 252 / | HD | COMPOSITIONS |
| 500 | DF | ELECTRICALLY CONDUCTIVE OR EMISSIVE COMPOSITIONS {6} |
| 518.1 | DF | .~ Metal compound containing {16} |
| 519.1 | DF | .~.~ Compound viewed as composition (i.e., wherein atoms or molecules in a chemical formula are not present as whole small integer values or cannot be multiplied by a single-digit factor to yield integer values) {4} |
| 519.14 | | .~.~.~ Sulfur, tellurium, selenium, nitrogen, phosphorus, or boron containing |