| 502 / | HD | CATALYST, SOLID SORBENT, OR SUPPORT THEREFOR: PRODUCT OR PROCESS OF MAKING |
| 100 | DF | CATALYST OR PRECURSOR THEREFOR {12} |
| 300 | DF | .~ Metal, metal oxide or metal hydroxide {10} |
| 349 | DF | .~.~ Of Group IV (i.e., Ti, Zr, Hf, Ge, Sn or Pb) {2} |
| 352 | | .~.~.~ Of tin |