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Lutetium

2007 Schools Wikipedia Selection. Related subjects: Chemical elements


                71             ytterbium ← lutetium → hafnium
                 Y
                ↑
                Lu
                ↓
                Lr

                                  Periodic Table - Extended Periodic Table

                                                                   General
                                     Name, Symbol, Number lutetium, Lu, 71
                                         Chemical series Transition metals
                                              Group, Period, Block 3, 6, d
                                                  Appearance silvery white
                                             Atomic mass 174.967 (1) g/mol
                                 Electron configuration Xe 6s^2 4f^14 5d^1
                                    Electrons per shell 2, 8, 18, 32, 9, 2
                                                       Physical properties
                                                               Phase solid
                                      Density (near r.t.) 9.841 g·cm^−3
                                     Liquid density at m.p. 9.3 g·cm^−3
                                                     Melting point 1925  K
                                                    (1652 ° C, 3006 ° F)
                                                      Boiling point 3675 K
                                                    (3402 ° C, 6156 ° F)
                                        Heat of fusion ca. 22 kJ·mol^−1
                                     Heat of vaporization 414 kJ·mol^−1
                          Heat capacity (25 °C) 26.86 J·mol^−1·K^−1

   CAPTION: Vapor pressure

                                 P/Pa   1    10  100   1 k    10 k  100 k
                                at T/K 1906 2103 2346 (2653) (3072) (3663)

                                                         Atomic properties
                                               Crystal structure hexagonal
                                                        Oxidation states 3
                                                      (weakly basic oxide)
                                    Electronegativity 1.27 (Pauling scale)
                                                       Ionization energies
                                           ( more) 1st: 523.5 kJ·mol^−1
                                                    2nd: 1340 kJ·mol^−1
                                                  3rd: 2022.3 kJ·mol^−1
                                                      Atomic radius 175 pm
                                              Atomic radius (calc.) 217 pm
                                                    Covalent radius 160 pm
                                                             Miscellaneous
                                                 Magnetic ordering no data
                          Electrical resistivity ( r.t.) (poly) 582 nΩ·m
                       Thermal conductivity (300 K) 16.4 W·m^−1·K^−1
                           Thermal expansion ( r.t.) (poly) 9.9 µm/(m·K)
                                                  Young's modulus 68.6 GPa
                                                    Shear modulus 27.2 GPa
                                                     Bulk modulus 47.6 GPa
                                                       Poisson ratio 0.261
                                                 Vickers hardness 1160 MPa
                                                  Brinell hardness 893 MPa
                                             CAS registry number 7439-94-3
                                                         Selected isotopes

                 CAPTION: Main article: Isotopes of lutetium

                            iso     NA    half-life   DM  DE ( MeV)   DP
                           ^173Lu syn    1.37 y       ε   0.671     ^173Yb
                           ^174Lu syn    3.31 y       ε   1.374     ^174Yb
                           ^175Lu 97.41% Lu is stable with 104 neutrons
                           ^176Lu 2.59%  3.78×10^10 y β^- 1.193     ^176Hf

                                                                References

   Lutetium ( IPA: /l(j)uːˈtiːʃiəm/) is a chemical element with the symbol
   Lu and atomic number 71. A metallic element of the transition metal
   group, lutetium usually occurs in association with yttrium and is
   sometimes used in metal alloys and as a catalyst in various processes.
   Though it is a transition metal according to factors like its place in
   the Periodic Table, its electron orbital configuration, and its
   physical properties, it is often grouped with the lanthanides.

Notable characteristics and applications

   Lutetium is a silvery white corrosion-resistant trivalent metal that is
   relatively stable in air and is the heaviest and hardest of the rare
   earth elements.

   This element is very expensive to obtain in useful quantities and
   therefore it has very few commercial uses. However, stable lutetium can
   be used as catalysts in petroleum cracking in refineries and can also
   be used in alkylation, hydrogenation, and polymerization applications.

   Lutetium aluminium garnet (Al[5]Lu[3]O[12]) has been proposed for use
   as a lens material in high refractive index immersion lithography.

   Cerium-doped lutetium oxyorthosilicate (LSO) is currently the preferred
   compound for detectors in positron emission tomography (PET.)

History

   Lutetium (Latin Lutetia meaning Paris) was independently discovered in
   1907 by French scientist Georges Urbain and Austrian mineralogist Baron
   Carl Auer von Welsbach. Both men found lutetium as an impurity in the
   mineral ytterbia which was thought by Swiss chemist Jean Charles
   Galissard de Marignac (and most others) to consist entirely of the
   element ytterbium.

   The separation of lutetium from Marignac's ytterbium was first
   described by Urbain and the naming honour therefore went to him. He
   chose the names neoytterbium (new ytterbium) and lutecium for the new
   element but neoytterbium was eventually reverted back to ytterbium and
   in 1949 the spelling of element 71 was changed to lutetium.

   Welsbach proposed the names cassiopium for element 71 (after the
   constellation Cassiopeia) and albebaranium for the new name of
   ytterbium but these naming proposals where rejected (although many
   German scientists in the 1950s called the element 71 cassiopium).

Occurrence

   Found with almost all other rare-earth metals but never by itself,
   lutetium is very difficult to separate from other elements.
   Consequently, it is also one of the most expensive metals, costing
   about six times as much per gram as gold.

   The principal commercially viable ore of lutetium is the rare earth
   phosphate mineral monazite: (Ce, La, etc.)PO[4] which contains 0.003%
   of the element. Pure lutetium metal has only relatively recently been
   isolated and is very difficult to prepare (thus it is one of the most
   rare and expensive of the rare earth metals). It is separated from
   other rare earth elements by ion exchange and then obtained in the
   elemental form by reduction of anhydrous LuCl[3] or LuF[3] by either an
   alkali metal or alkaline earth metal.

Isotopes

   Naturally occurring lutetium is composed of 1 stable isotope Lu-175
   (97.41% natural abundance). 33 radioisotopes have been characterized,
   with the most stable being Lu-176 with a half-life of 3.78 × 10^10
   years (2.59% natural abundance), Lu-174 with a half-life of 3.31 years,
   and Lu-173 with a half-life of 1.37 years. All of the remaining
   radioactive isotopes have half-lifes that are less than 9 days, and the
   majority of these have half lifes that are less than a half an hour.
   This element also has 18 meta states, with the most stable being
   Lu-177m (t[½] 160.4 days), Lu-174m (t[½] 142 days) and Lu-178m (t[½]
   23.1 minutes).

   The isotopes of lutetium range in atomic weight from 149.973 (Lu-150)
   to 183.961 (Lu-184). The primary decay mode before the most abundant
   stable isotope, Lu-175, is electron capture (with some alpha and
   positron emission), and the primary mode after is beta emission. The
   primary decay products before Lu-175 are element 70 (ytterbium)
   isotopes and the primary products after are element 72 (hafnium)
   isotopes.

Compounds

   Fluoride: LuF[3], Chloride: LuCl[3], Bromide: LuBr[3], Iodide: LuI[3],
   Oxide: Lu[2]O[3], Sulfide: Lu[2]S[3], Nitride: LuN

   Intermetalic compounds:
     * Lutetium aluminium garnet

Precautions

   Like other rare-earth metals lutetium is regarded as having a low
   toxicity rating but it and especially its compounds should be handled
   with care nonetheless. Metal dust of this element is a fire and
   explosion hazard. Lutetium plays no biological role in the human body
   but is thought to help stimulate metabolism.
   Retrieved from " http://en.wikipedia.org/wiki/Lutetium"
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   with only minor checks and changes (see www.wikipedia.org for details
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