lutetium

American  

[loo-tee-shee-uhm] / luˈti ʃi əm /

Or lutecium

noun

Chemistry.

1. a trivalent rare-earth element. Lu; 174.97; 71.

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lutetium British  

/ lʊˈtiːʃɪəm /

noun

1. a silvery-white metallic element of the lanthanide series, occurring in monazite and used as a catalyst in cracking, alkylation, and polymerization. Symbol: Lu; atomic no: 71; atomic wt: 174.967; valency: 3; relative density: 9.841; melting pt: 1663°C; boiling pt: 3402°C

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lutetium Scientific  

/ lo̅o̅-tē′shē-əm /

1. A silvery-white metallic element of the lanthanide series that is used in nuclear technology. Its radioactive isotope is used in determining the age of meteorites. Atomic number 71; atomic weight 174.97; melting point 1,663°C; boiling point 3,395°C; specific gravity 9.840 (at 25°C); valence 3.

2. See Periodic Table

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Etymology

Origin of lutetium

1905–10; < Latin Lūtēt ( ia ) Paris + -ium

Example Sentences

The region holds deposits of many of the very elements China has placed under export controls: yttrium, scandium, erbium, europium, ytterbium, samarium, and lutetium.

From Barron's • Oct. 24, 2025

This unusual imbalance suggested that liquid water had once seeped through the rocks, effectively leaching lutetium out of them.

From Science Daily • Oct. 16, 2025

The 17 elements are: lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium, yttrium.

From Reuters • Jul. 5, 2023

Salamat has used imaging methods that reveal where the heavy lutetium atoms are within the compound, but the team isn’t yet certain about the configuration of the lighter hydrogen and nitrogen atoms.

From Scientific American • Mar. 10, 2023

The team at Rochester started with a small, thin foil of lutetium, a silvery white metal that is among the rarest of rare earth elements, and pressed it between two interlocking diamonds.

From New York Times • Mar. 8, 2023