Lutetium
A rare earth element discovered amid priority disputes.
Lutetium is a chemical element with symbol Lu and atomic number 71. It is a silvery white metal that resists corrosion in dry air but not in moist air, and it is the last element in the lanthanide series, traditionally counted among the rare earth elements.
- symbol
- Lu
- atomic_number
- 71
- discoverers
- Georges Urbain, Carl Auer von Welsbach, Charles James
- category
- Lanthanide / Transition metal
Lore & Background
Georges Urbain published first, followed by Carl Auer von Welsbach; Charles James, who had the largest supply, withdrew his claim upon learning of Urbain's work. A dispute arose between Urbain and Welsbach, each accusing the other of publishing results influenced by the other's research. Welsbach's proposed name cassiopeium was used by many German scientists until the 1950s.
Reader's Guide
Lutetium is not particularly abundant but is more common than silver in the Earth's crust. Lutetium is also used in metal alloys and as a catalyst. Its physical properties are notable: it has the smallest atom among lanthanides due to lanthanide contraction, and the highest density, melting point, and hardness. Chemically, lutetium almost always exhibits the +3 oxidation state, and its compounds are typically colorless. The element's history reflects early 20th-century scientific rivalries and the evolving standards of element naming, with the name lutetium ultimately prevailing despite challenges.
Frequently Asked Questions
Who is Lutetium?
Lutetium is a silvery-white metal carrying the symbol Lu and atomic number 71, sitting at the very tail end of the lanthanide row. It is traditionally grouped with the rare earth elements and is the heaviest member of that family.
How does Lutetium's story end?
As element 71, Lutetium closes out the entire lanthanide series, serving as the final act before the table moves into the heavier transition metals. Its position marks the end of the rare-earth family in the periodic layout.
Why is Lutetium important?
Being the hardest and heaviest lanthanide, Lutetium plays a niche but valuable role in specialized alloys and optical applications. Its rarity and terminal position make it a key reference point for understanding the full scope of the rare-earth family.
More in Periodic Table & Elements 1-21
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