CAS: 7439-94-3
Description: Silvery metal
Classification: Rare Earth (Lanthanide)
Date of Discovery: 1907
Discoverer: Georges Urbain
Name Origin:Lutetia, "Paris"
Alternative Name: Cassiopeium (Germany)
Atomic Number: 71
Number of Neutrons: 104
Atomic Mass: 174.967(1) amu
Melting Point: 1663 °C
Boiling Point: 3402 °C
Density (25 °C): 9.8841 g/cm3 Atomic volume: 17.78 cm3/mol
Electrical resistivity: 0.0185 10-6/cm Thermal conductivity: 0.164 W/cmK
Enthalpy of atomization: 398 kJ/mol (est.)
Enthalpy of vaporization: 355.90 kJ/mol
Enthalpy of fusion: 18.60 kJ/mol
Specific heat capacity: 0.15 J/gK
Energy levels: 2-8-18-32-9-2
Electron configuration: [Xe]4f 145d16s2 Crystal Structure: Hexagonal
Atomic radius: 2.25 Å
Covalent radius: 1.56 Å
Oxidation States: +3
Electronegativity, Pauling: 1.27
Electron affinity: First ionization energy: 5.43 eV
2nd ionization energy: 13.888 eV
3rd ionization energy: 20.957 eV
Polarizability: 21.9 10-24cm3
Isotope
Natural Abundance
Atomic Mass
Half-life
Decay Mode
Spin
150Lu
149.973
35 ms
p
151Lu
150.967
0.08 s
p
152Lu
151.963
0.7 s
-
153Lu
152.959
-
154Lu
153.9571
1.0 s
+, EC
155mLu
2.6 ms
155Lu
154.9542
0.07 s
EC;
156mLu
0.20 s
156Lu
155.9529
0.5 s
+, EC;
157mLu
9.6 s
157Lu
156.95010
4.8 s
+, EC;
158Lu
15794984
10.4 s
+, EC;
159Lu
158.9467
12.3 s
+, EC
160Lu
159.94654
36.1 s
+, EC
161Lu
160.9432
1.2 m
+, EC
162mLu
1.5 m
EC
4-
162Lu
161.9432
1.37 m
+, EC
1-
163Lu
162.9412
4.1 m
+, EC
164Lu
163.9412
3.14 m
+, EC
165Lu
164.9396
10.7 m
+, EC
1/2+
166m2Lu
2.1 m
+; EC
(0-)
166m1Lu
1.4 m
+, EC; IT
(3-)
166Lu
165.9398
2.8 m
+; EC
(6-)
167Lu
166.9383
52 m
+; EC
7/2+
168mLu
6.7 m
+; EC
3+
168Lu
167.9387
5.5 m
+; EC
(6-)
169mLu
2.7 m
IT
1/2-
169Lu
168.93765
1.419 d
EC
7/2+
170mLu
0.7 s
IT
4-
170Lu
169.93847
2.01 d
EC
0+
171mLu
1.31 m
IT
1/2-
171Lu
170.937910
8.24 d
EC
7/2+
172mLu
3.7 m
IT
1-
172Lu
171.939082
6.70 d
EC
4-
173Lu
172.938927
1.37 y
EC
7/2+
174mLu
142 d
IT; EC
6-
174Lu
173.940334
3.3 y
EC
1-
175Lu
97.41(2)
174.940768
Stable
7/2+
176mLu
3.66 h
-
1-
176Lu
2.59(2)
175.942683
3.8 x 1010 y
-
7-
177mLu
160.7 d
IT; -
23/2-
177Lu
176.943755
6.75 d
-
7/2+
178mLu
23.1 m
-
(9-)
178Lu
177.945952
28.5 m
-
1+
179Lu
178.94732
4.6 h
-
7/2+
180Lu
179.9499
5.7 m
-
181Lu
180.9518
3.5 m
-
(7/2+)
182Lu
2.0 m
-
183Lu
58 s
-
7/2+
In 1907, Urbain described a process by which Marignac's ytterbium (1879) could be separated into the two elements, ytterbium (neoytterbium)and lutetium. These elements were identical with "aldebaranium" and "cassiopeium," independently discovered by von Welsbach about the same time. Charles James of the University of New Hampshire also independently prepared the very pure oxide, lutecia, at this time. The spelling of
the element was changed from lutecium to lutetium in 1949. Lutetium occurs in very small amounts in nearly all minerals containing yttrium, and is present in monazite to the extent of about 0.003%, which is a commercial source. The pure metal has been isolated only in recent years and is one of the most difficult to prepare. It can be prepared by the reduction of anhydrous LuCl3 or LuF3 by an alkali or alkaline earth metal. The metal is silvery white and relatively stable in air. While new techniques, including ion-exchange reactions, have been developed to separate the various rare-earth elements, lutetium is still the most costly of all rare earths. 176Lu occurs naturally (97.41 %) with 175Lu (2.59%), which is radioactive with a very long half-life. It is radioactive with a half-life of about 4 x 1010 years. Lutetium has 49 isotopes and isomers that are now recognized. Stable lutetium nuclides, which emit pure beta radiation after thermal neutron activation, can be used as catalysts in cracking, alkylation, hydrogenation, and polymerization. Virtually no other commercial uses have been found yet for lutetium. While lutetium, like other rare-earth metals, is thought to have a low toxicity rating, it should be handled with care until more information is available.
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