Lutetium

Lutetium, ₇₁Lu
Lutetium
Pronunciation	/ljuːˈtiːʃiəm/ (lew-TEE-shee-əm)
Appearance	silvery white
Standard atomic weight Ar°(Lu)
	174.9668±0.0001; 174.97±0.01 (abridged);
Lutetium in the periodic table
	ytterbium ← lutetium → hafnium
Atomic number (Z)	71
Group	group 3
Period	period 6
Block	d-block
Electron configuration	[Xe] 4f14 5d1 6s2
Electrons per shell	2, 8, 18, 32, 9, 2
Physical properties
Phase at STP	solid
Melting point	1925 K (1652 °C, 3006 °F)
Boiling point	3675 K (3402 °C, 6156 °F)
Density (at 20° C)	9.840 g/cm3
when liquid (at m.p.)	9.3 g/cm3
Heat of fusion	ca. 22 kJ/mol
Heat of vaporization	414 kJ/mol
Molar heat capacity	26.86 J/(mol·K)
Atomic properties
Oxidation states	0, +1, +2, +3 (a weakly basic oxide)
Electronegativity	Pauling scale: 1.27
Ionization 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
	Spectral lines of lutetium
Other properties
Natural occurrence	primordial
Crystal structure	hexagonal close-packed (hcp) (hP2)
Lattice constants	a = 350.53 pm; c = 554.93 pm (at 20 °C)
Thermal expansion	poly: 9.9 µm/(m⋅K) (at r.t.)
Thermal conductivity	16.4 W/(m⋅K)
Electrical resistivity	poly: 582 nΩ⋅m (at r.t.)
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 Number	7439-94-3
History
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)
Isotopes of lutetium v; e;
	Category: Lutetium; view; talk; edit; \| references

Lutetium is a chemical element; it has symbol Lu and atomic number 71. It is a silvery white metal, which resists corrosion in dry air, but not in moist air. Lutetium is the last element in the lanthanide series, and it is traditionally counted among the rare earth elements; it can also be classified as the first element of the 6th-period transition metals.^[7]

Lutetium was independently discovered in 1907 by French scientist Georges Urbain, Austrian mineralogist Baron Carl Auer von Welsbach, and American chemist Charles James.^[8] All of these researchers found lutetium as an impurity in the mineral ytterbia, which was previously thought to consist entirely of ytterbium. The dispute on the priority of the discovery occurred shortly after, with Urbain and Welsbach accusing each other of publishing results influenced by the published research of the other; the naming honor went to Urbain, as he had published his results earlier. He chose the name lutecium for the new element, but in 1949 the spelling was changed to lutetium. In 1909, the priority was finally granted to Urbain and his names were adopted as official ones; however, the name cassiopeium (or later cassiopium) for element 71 proposed by Welsbach was used by many German scientists until the 1950s.^[9]

Lutetium is not a particularly abundant element, although it is significantly more common than silver in the Earth's crust. It has few specific uses. Lutetium-176 is a relatively abundant (2.5%) radioactive isotope with a half-life of about 38 billion years, used to determine the age of minerals and meteorites. Lutetium usually occurs in association with the element yttrium^[10] and is sometimes used in metal alloys and as a catalyst in various chemical reactions. ¹⁷⁷Lu-DOTA-TATE is used for radionuclide therapy (see Nuclear medicine) on neuroendocrine tumours. Lutetium has the highest Brinell hardness of any lanthanide, at 890–1300 MPa.^[11]

^ "Standard Atomic Weights: Lutetium". CIAAW. 2007.
^ Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.
^ ^a ^b Arblaster, John W. (2018). Selected Values of the Crystallographic Properties of Elements. Materials Park, Ohio: ASM International. ISBN 978-1-62708-155-9.
^ Yttrium and all lanthanides except Ce and Pm have been observed in the oxidation state 0 in bis(1,3,5-tri-t-butylbenzene) complexes, see Cloke, F. Geoffrey N. (1993). "Zero Oxidation State Compounds of Scandium, Yttrium, and the Lanthanides". Chem. Soc. Rev. 22: 17–24. doi:10.1039/CS9932200017. and Arnold, Polly L.; Petrukhina, Marina A.; Bochenkov, Vladimir E.; Shabatina, Tatyana I.; Zagorskii, Vyacheslav V.; Cloke (2003-12-15). "Arene complexation of Sm, Eu, Tm and Yb atoms: a variable temperature spectroscopic investigation". Journal of Organometallic Chemistry. 688 (1–2): 49–55. doi:10.1016/j.jorganchem.2003.08.028.
^ Lide, D. R., ed. (2005). "Magnetic susceptibility of the elements and inorganic compounds". CRC Handbook of Chemistry and Physics (PDF) (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5.
^ Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.
^ Scerri, E. (2012). "Mendeleev's Periodic Table Is Finally Completed and What To Do about Group 3?". Chemistry International. 34 (4). doi:10.1515/ci.2012.34.4.28. Archived from the original on 5 July 2017.
^ "Lutetium Element Facts / Chemistry".
^ "History of Lutetium".
^ "lutetium - Dictionary Definition". Vocabulary.com. Retrieved 2020-03-06.
^ Samsonov, G. V., ed. (1968). "Mechanical Properties of the Elements". Handbook of the physicochemical properties of the elements. New York, USA: IFI-Plenum. pp. 387–446. doi:10.1007/978-1-4684-6066-7_7. ISBN 978-1-4684-6066-7. Archived from the original on 2015-04-02.

[1] "Standard Atomic Weights: Lutetium". CIAAW. 2007.

[CIAAW2021-2] Prohaska, Thomas; Irrgeher, Johanna; Benefield, Jacqueline; Böhlke, John K.; Chesson, Lesley A.; Coplen, Tyler B.; Ding, Tiping; Dunn, Philip J. H.; Gröning, Manfred; Holden, Norman E.; Meijer, Harro A. J. (2022-05-04). "Standard atomic weights of the elements 2021 (IUPAC Technical Report)". Pure and Applied Chemistry. doi:10.1515/pac-2019-0603. ISSN 1365-3075.

[Arblaster_2018-3] Arblaster, John W. (2018). Selected Values of the Crystallographic Properties of Elements. Materials Park, Ohio: ASM International. ISBN 978-1-62708-155-9.

[Cloke1993-4] Yttrium and all lanthanides except Ce and Pm have been observed in the oxidation state 0 in bis(1,3,5-tri-t-butylbenzene) complexes, see Cloke, F. Geoffrey N. (1993). "Zero Oxidation State Compounds of Scandium, Yttrium, and the Lanthanides". Chem. Soc. Rev. 22: 17–24. doi:10.1039/CS9932200017. and Arnold, Polly L.; Petrukhina, Marina A.; Bochenkov, Vladimir E.; Shabatina, Tatyana I.; Zagorskii, Vyacheslav V.; Cloke (2003-12-15). "Arene complexation of Sm, Eu, Tm and Yb atoms: a variable temperature spectroscopic investigation". Journal of Organometallic Chemistry. 688 (1–2): 49–55. doi:10.1016/j.jorganchem.2003.08.028.

[magnet-5] Lide, D. R., ed. (2005). "Magnetic susceptibility of the elements and inorganic compounds". CRC Handbook of Chemistry and Physics (PDF) (86th ed.). Boca Raton (FL): CRC Press. ISBN 0-8493-0486-5.

[NUBASE2020-6] Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S.; Audi, G. (2021). "The NUBASE2020 evaluation of nuclear properties" (PDF). Chinese Physics C. 45 (3): 030001. doi:10.1088/1674-1137/abddae.

[finally-7] Scerri, E. (2012). "Mendeleev's Periodic Table Is Finally Completed and What To Do about Group 3?". Chemistry International. 34 (4). doi:10.1515/ci.2012.34.4.28. Archived from the original on 5 July 2017.

[:0-8] "Lutetium Element Facts / Chemistry".

[9] "History of Lutetium".

[10] "lutetium - Dictionary Definition". Vocabulary.com. Retrieved 2020-03-06.

[11] Samsonov, G. V., ed. (1968). "Mechanical Properties of the Elements". Handbook of the physicochemical properties of the elements. New York, USA: IFI-Plenum. pp. 387–446. doi:10.1007/978-1-4684-6066-7_7. ISBN 978-1-4684-6066-7. Archived from the original on 2015-04-02.

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