Lutetium
Definition and meaning of Lutetium in chemistry.
![Lutetium element card: symbol Lu, atomic number 71, atomic mass 174.97, electron configuration [Xe] 4f¹⁴ 5d¹ 6s², oxidation states +3, Lanthanide, f-block, period 6, solid at room temperature.](/assets/images/terms/lutetium-chemical-element.webp)
Lutetium is a chemical element with the symbol Lu and atomic number 71. This dense, silvery-white metal marks the final element located in the lanthanide series. Chemists characterize this specific rare earth metal by its extreme physical hardness and high density.
In more detail
Lutetium stands out as the hardest and densest of all the known lanthanides. It possesses a noticeably higher melting point and boiling point than its periodic table neighbors. You will never find it existing as a free, pure element in nature.
Instead, miners must extract trace quantities from complex phosphate minerals like monazite and xenotime. Chemically, the solid metal strongly resists oxidation when exposed to completely dry air. However, it will slowly tarnish in moist air environments and readily dissolves in most weak aqueous acids.
Lutetium sits at the very end of the f-block on the periodic table. This unique position on the periodic table gives the atom a completely filled f-orbital. This filled electron orbital forces the element to be strictly trivalent (+3) in all its stable chemical compounds.
Lutetium is extremely scarce and hard to find throughout the Earth's crust. Furthermore, separating it from chemically similar rare earths requires immense time, energy, and effort. These challenging extraction factors make lutetium one of the most expensive metallic elements available in the world. Consequently, the rare metal currently has very few large-scale commercial or industrial applications.
Key facts
| Field | General Chemistry |
|---|---|
| Symbol | Lu |
| Atomic number | 71 |
| Atomic mass | 174.97 u |
| Category | Lanthanide |
| State at room temperature | Solid |
Doctors increasingly utilize the radioactive isotope lutetium-177 in advanced targeted radionuclide therapies in modern medicine. This powerful medical isotope selectively delivers destructive beta radiation to certain types of severe neuroendocrine tumors. It also effectively helps doctors treat patients struggling with progressive prostate cancers.
Frequently asked questions
Why is lutetium among the most expensive elements to purchase?
Its high cost stems directly from its exceptionally low natural abundance. Additionally, it requires complex, energy-intensive chemical separation processes to isolate it from other rare earth metals.
Where does the elemental name lutetium originate?
The name comes directly from Lutetia. This was the ancient Roman name for the settlement that eventually became the modern city of Paris, France.
Related terms
Sources & references
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