Lanthanide
Noun
lanthanide
(plural lanthanides)- (chemistry) Any of the 14 rare earth elements from cerium (or from lanthanum) to lutetium in the periodic table; because their outermost orbitals are empty, they have very similar chemistry; below them are the actinides.
Usage notes
According to IUPAC - "Although lanthanoid means 'like lanthanum' and so should not include lanthanum, lanthanum has become included by common usage. Similarly, actinoid. The ending 'ide' normally indicates a negative ion, and therefore lanthanoid and actinoid are preferred to lanthanide and actinide. However, lanthanide and actinide are still allowed owing to wide current use."
Synonyms
- lanthanate obsolete
- lanthanoid (including lanthanum)
- lanthanon (proposed to avoid confusion with the usual meaning in chemistry of -ide)
- rare-earth element