SymbolLu
Latin nameLutecium
Atomic number71
Period6
Element categoryInner transition elements
Relative atomic mass174.967
GroupIII.B
Electronegativity
1.2
Oxidation numbers
3
Electron configuration
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d1 6s2
Density [g/cm3]
9.842
State
Solid
Melting point [°C]
1663
Boiling point [°C]
3395
Atomic radius [pm]
217
Covalent radius [pm]
160
Thermal conductivity [W m-1K-1]
16.4
Heat capacity [J K-1g-1]
0.15
Discovery
1907
Vickers hardness [MPa]
1160
Brinell hardness [MPa]
893
Young's modulus [GPa]
69
Electrical conductivity [S m-1]
1.8 · 106
Shear modulus [GPa]
27
1.st ionization energy [eV]
5.4259
2.nd ionization energy [eV]
13.888
3.rd ionization energy [eV]
20.957
Stable isotopes
2
Unstable isotopes
21