Explanatory notes
… neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium). … could be conceived as having been made intentionally for special purposes and which, accordingly, fall in heading … compounds of rare‑earth metals, e.g., xenotime (complex phosphates), gadolinite or ytterbite and cerite (complex …