lanthanide

From lanthanium +‎ -ide.

• enPR: lăn'thənīd, IPA^(key): /ˈlænθənaɪd/

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lanthanide (plural lanthanides)

1. (chemistry) Any of the 15 rare earth elements from lanthanum to lutetium in the periodic table; because their outermost orbitals are not filled, they have very similar chemistry; below them are the actinides.
2. (chemistry) Any of the 14 rare earth elements from lanthanum to ytterbium (lutetium is excluded by some authors as it is a d-block rather than an f-block element).
3. (chemistry, dated) Any of the 14 rare earth elements from cerium to lutetium (lanthanum having been excluded because it was thought to be a d-block element in the past).

• 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."

• lanthanate (obsolete)
• lanthanoid (including lanthanum)
• lanthanon (proposed to avoid confusion with the usual meaning in chemistry of -ide)
• rare-earth element

• lanthanide contraction
• lanthanide series

• lanthanum
• cerium
• praseodymium
• neodymium
• promethium
• samarium
• europium
• gadolinium
• terbium
• dysprosium
• holmium
• erbium
• thulium
• ytterbium
• lutetium

lanthanide m (plural lanthanides)

1. lanthanide

• “lanthanide”, in Trésor de la langue française informatisé [Digitized Treasury of the French Language], 2012.