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Dysprosium

2007 Schools Wikipedia Selection. Related subjects: Chemical elements


                66             terbium ← dysprosium → holmium
                 -
                ↑
                Dy
                ↓
                Cf

                                  Periodic Table - Extended Periodic Table

                                                                   General
                                   Name, Symbol, Number dysprosium, Dy, 66
                                               Chemical series lanthanides
                                            Group, Period, Block n/a, 6, f
                                                  Appearance silvery white
                                             Atomic mass 162.500 (1) g/mol
                                    Electron configuration [Xe] 4f^10 6s^2
                                    Electrons per shell 2, 8, 18, 28, 8, 2
                                                       Physical properties
                                                               Phase solid
                                      Density (near r.t.) 8.540 g·cm^−3
                                    Liquid density at m.p. 8.37 g·cm^−3
                                                     Melting point 1680  K
                                                    (1407 ° C, 2565 ° F)
                                                      Boiling point 2840 K
                                                    (2567 ° C, 4653 ° F)
                                         Heat of fusion 11.06 kJ·mol^−1
                                     Heat of vaporization 280 kJ·mol^−1
                           Heat capacity (25 °C) 27.7 J·mol^−1·K^−1

   CAPTION: Vapor pressure

                               P/Pa   1    10   100    1 k    10 k  100 k
                              at T/K 1378 1523 (1704) (1954) (2304) (2831)

                                                         Atomic properties
                                               Crystal structure hexagonal
                                                        Oxidation states 3
                                                      (weakly basic oxide)
                                    Electronegativity 1.22 (Pauling scale)
                                                       Ionization energies
                                           ( more) 1st: 573.0 kJ·mol^−1
                                                    2nd: 1130 kJ·mol^−1
                                                    3rd: 2200 kJ·mol^−1
                                                      Atomic radius 175 pm
                                              Atomic radius (calc.) 228 pm
                                                             Miscellaneous
                                    Magnetic ordering nonmagnetic at r.t.,
                                                       ferromagnetic under
                                                           liquid nitrogen
                      Electrical resistivity ( r.t.) (α, poly) 926 nΩ·m
                       Thermal conductivity (300 K) 10.7 W·m^−1·K^−1
                                      Thermal expansion ( r.t.) (α, poly)
                                                            9.9 µm/(m·K)
                               Speed of sound (thin rod) (20 °C) 2710 m/s
                                        Young's modulus (α form) 61.4 GPa
                                          Shear modulus (α form) 24.7 GPa
                                           Bulk modulus (α form) 40.5 GPa
                                             Poisson ratio (α form) 0.247
                                                  Vickers hardness 540 MPa
                                                  Brinell hardness 500 MPa
                                             CAS registry number 7429-91-6
                                                         Selected isotopes

                CAPTION: Main article: Isotopes of dysprosium

                                iso     NA   half-life DM DE ( MeV)   DP
                               ^154Dy syn    3.0×10^6y α  2.947     ^150Gd
                               ^156Dy 0.06%  Dy is stable with 90 neutrons
                               ^158Dy 0.10%  Dy is stable with 92 neutrons
                               ^160Dy 2.34%  Dy is stable with 94 neutrons
                               ^161Dy 18.91% Dy is stable with 95 neutrons
                               ^162Dy 25.51% Dy is stable with 96 neutrons
                               ^163Dy 24.90% Dy is stable with 97 neutrons
                               ^164Dy 28.18% Dy is stable with 98 neutrons

                                                                References

   Dysprosium ( IPA: /dɪsˈprəʊziəm/) is a chemical element in the periodic
   table that has the symbol Dy and atomic number 66.

Notable characteristics

   Dysprosium is a rare earth element that has a metallic, bright silver
   luster, relatively stable in air at room temperature, but dissolving
   readily in dilute or concentrated mineral acids with the emission of
   hydrogen. It is soft enough to be cut with bolt-cutters (but not with a
   knife), and can be machined without sparking if overheating is avoided.
   Dysprosium's characteristics can be greatly affected even by small
   amounts of impurities.

Applications

   Dysprosium is used, in conjunction with vanadium and other elements, in
   making laser materials. Its high thermal neutron absorption
   cross-section and melting point also suggests that it is useful for
   nuclear control rods. Dysprosium oxide (also known as dysprosia), with
   nickel cement compounds, which absorb neutrons readily without swelling
   or contracting under prolonged neutron bombardment, is used for cooling
   rods in nuclear reactors. Dysprosium-cadmium chalcogenides are sources
   of infrared radiation for studying chemical reactions. Furthermore,
   dysprosium is used for manufacturing compact discs. Because it is
   highly paramagnetic, dysprosium has been used as a contrast agent in
   magnetic resonance imaging.

History

   Dysprosium was first identified in Paris in 1886 by French chemist Paul
   Émile Lecoq de Boisbaudran. However, the element itself was not
   isolated in relatively pure form until after the development of ion
   exchange and metallographic reduction techniques in the 1950s. The name
   dysprosium is derived from the Greek δυσπροσιτος [dysprositos] = "hard
   to obtain".

Occurrence

   Dysprosium is never encountered as a free element, but is found in many
   minerals, including xenotime, fergusonite, gadolinite, euxenite,
   polycrase, blomstrandine, monazite and bastnasite; often with erbium
   and holmium or other rare earth elements.

Compounds

   Nearly all dysprosium compounds are in the +3 oxidation state, and are
   highly paramagnetic. Dysprosium compounds include:
     * Fluorides
          + DyF[3]
     * Chlorides
          + DyCl[2]
          + DyCl[3]
     * Bromides
          + DyBr[2]
          + DyBr[3]
     * Iodides
          + DyI[2]
          + DyI[3]
     * Oxides
          + Dy[2]O[3]
     * Sulfides
          + Dy[2]S[3]
     * Nitrides
          + DyN

Isotopes

   Naturally occurring dysprosium is composed of 7 stable isotopes,
   156-Dy, 158-Dy, 160-Dy, 161-Dy, 162-Dy, 163-Dy and 164-Dy, with 164-Dy
   being the most abundant (28.18% natural abundance). 28 radioisotopes
   have been characterized, with the most stable being 154-Dy with a
   half-life of 3.0E+6 years, 159-Dy with a half-life of 144.4 days, and
   166-Dy with a half-life of 81.6 hours. All of the remaining radioactive
   isotopes have half-lifes that are less than 10 hours, and the majority
   of these have half lifes that are less than 30 seconds. This element
   also has 5 meta states, with the most stable being 165m-Dy (t[½] 1.257
   minutes), 147m-Dy (t[½] 55.7 seconds) and 145m-Dy (t[½] 13.6 seconds).

   The primary decay mode before the most abundant stable isotope, 164-Dy,
   is electron capture, and the primary mode after is beta minus decay.
   The primary decay products before 164-Dy are terbium isotopes, and the
   primary products after are holmium isotopes.

Precautions

   As with the other lanthanides, dysprosium compounds are of low to
   moderate toxicity, although their toxicity has not been investigated in
   detail. Dysprosium does not have any known biological properties.
   Retrieved from " http://en.wikipedia.org/wiki/Dysprosium"
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   with only minor checks and changes (see www.wikipedia.org for details
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