252 / | HD | COMPOSITIONS |
500 | DF | ELECTRICALLY CONDUCTIVE OR EMISSIVE COMPOSITIONS {6} |
518.1 | DF | .~ Metal compound containing {16} |
520.2 | DF | .~.~ Titanium or zirconium compound {2} |
520.22 | ![]() | .~.~.~ Boron, silicon, phosphorus, nitrogen, hydrogen, carbon, or halogen containing |