| 252 / | HD | COMPOSITIONS |
| * | DD | FOREIGN ART COLLECTIONS {1} |
| FOR 251 | | .~ Metal compound containing (252/518) {3} |
| FOR 252 | DD | .~.~> Iron group compound (252/519) |
| FOR 253 | DD | .~.~> Titanium or zirconium compound (252/520) |
| FOR 254 | DD | .~.~> Magnesium, alkaline earth metal, or rare earth metal compound (252/521) |