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Lutetium,  71Lu
General properties
Name, symbol Lutetium, Lu
Appearance Silvery-white
Lutetium in the periodic table


Atomic number 71
Standard atomic weight (Ar) 174.9668(1)
Group, block , f-block
Period period 6
Electron configuration [Xe] 4f14 5d1 6s2
per shell
2, 8, 18, 32, 9, 2
Physical properties
Phase Solid
Melting point 1925 K ​(1652 °C, ​3006 °F)
Boiling point 3675 K ​(3402 °C, ​​6156 °F)
Density near r.t. 9.841 g/cm3
when liquid, at  9.3 g/cm3
Heat of fusion 22 kJ/mol
Heat of 414 kJ/mol
Molar heat capacity 26.86 J/(mol·K)
Atomic properties
Oxidation states 3, 2, 1 ​(a weakly basic oxide)
Electronegativity Pauling scale: 1.27
energies 1st: 523.5 kJ/mol
2nd: 1340 kJ/mol
3rd: 2022.3 kJ/mol
Atomic radius empirical: 174 pm
Covalent radius 187±8 pm
Crystal structure ​Hexagonal close-packed (hcp)
Thermal expansion 9.9 µm/(m·K) (poly)
Thermal conductivity 16.4 W/(m·K)
Electrical resistivity 5.82·10-7 Ω·m (poly)
Magnetic ordering Paramagnetic
Young's modulus 68.6 GPa
Shear modulus 27.2 GPa
Bulk modulus 47.6 GPa
Poisson ratio 0.261
Vickers hardness 755–1160 MPa
Brinell hardness 890–1300 MPa
CAS Registry Number 7439-94-3
Naming After Lutetia, Latin for: Paris, in the Roman era
Discovery Carl Auer von Welsbach and Georges Urbain (1906)
First isolation Carl Auer von Welsbach (1906)
Named by Georges Urbain (1906)
· references

Lutetium is a chemical element with symbol Lu and atomic number 71. It is considered the first element of the 6th-period transition metals and the last element in the lanthanide series, and is traditionally counted among the rare earths.

Lutetium's position in the periodic table is not entirely agreed on. Some models put it in group 3, others at the end of the f block with lanthanum and actinium instead, while other types of tables only have scandium and yttrium, leaving lutetium in the f block.



Like most lanthanides, lutetium resists oxidation in dry air, but will slowly react with water. Lutetium dissolves readily in both strong and weak acids, with the nitrate, sulfate and acetate salts being soluble in water, while the fluoride, carbonate, phosphate and oxalate salts are insoluble in water.


Lutetium is a silvery white metal. It has a meting point of 1652 °C and a boiling point of 3402 °C. Its density is 9.841 g/cm3.


Lutetium can be purchased from Metallium and eBay.


Reducing lutetium salts, like lutetium(III) chloride with calcium metal will yield lutetium metal.


  • Element collecting
  • Make lutetium compounds
  • Make lutetium aluminium garnet
  • Make lutetium tantalate



Lutetium reacts with water to release hydrogen, which is flammable.

Luthetium compounds are thought to be non-toxic. At least one compound, Motexafin lutetium has been studied in cancer treatment.


Luthetium should be kept in closed containers, away from moisture and acids.


Since lutetium is expensive, it's best to try to recycle it.


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