Gadolinium

  • gadolinium, 64gd
    gadolinium-4.jpg
    gadolinium
    pronunciationm/ (lin-ee-əm)
    appearancesilvery white
    standard atomic weight ar, std(gd)157.25(3)[1]
    gadolinium in the periodic table
    hydrogen helium
    lithium beryllium boron carbon nitrogen oxygen fluorine neon
    sodium magnesium aluminium silicon phosphorus sulfur chlorine argon
    potassium calcium scandium titanium vanadium chromium manganese iron cobalt nickel copper zinc gallium germanium arsenic selenium bromine krypton
    rubidium strontium yttrium zirconium niobium molybdenum technetium ruthenium rhodium palladium silver cadmium indium tin antimony tellurium iodine xenon
    caesium barium lanthanum cerium praseodymium neodymium promethium samarium europium gadolinium terbium dysprosium holmium erbium thulium ytterbium lutetium hafnium tantalum tungsten rhenium osmium iridium platinum gold mercury (element) thallium lead bismuth polonium astatine radon
    francium radium actinium thorium protactinium uranium neptunium plutonium americium curium berkelium californium einsteinium fermium mendelevium nobelium lawrencium rutherfordium dubnium seaborgium bohrium hassium meitnerium darmstadtium roentgenium copernicium nihonium flerovium moscovium livermorium tennessine oganesson


    gd

    cm
    europiumgadoliniumterbium
    atomic number (z)64
    groupgroup n/a
    periodperiod 6
    blockf-block
    element category  lanthanide
    electron configuration[xe] 4f7 5d1 6s2
    electrons per shell2, 8, 18, 25, 9, 2
    physical properties
    phase at stpsolid
    melting point1585 k ​(1312 °c, ​2394 °f)
    boiling point3273 k ​(3000 °c, ​5432 °f)
    density (near r.t.)7.90 g/cm3
    when liquid (at m.p.)7.4 g/cm3
    heat of fusion10.05 kj/mol
    heat of vaporization301.3 kj/mol
    molar heat capacity37.03 j/(mol·k)
    vapor pressure (calculated)
    p (pa) 1 10 100 1 k 10 k 100 k
    at t (k) 1836 2028 2267 2573 2976 3535
    atomic properties
    oxidation states0,[2] +1, +2, +3 (a mildly basic oxide)
    electronegativitypauling scale: 1.20
    ionization energies
    • 1st: 593.4 kj/mol
    • 2nd: 1170 kj/mol
    • 3rd: 1990 kj/mol
    atomic radiusempirical: 180 pm
    covalent radius196±6 pm
    color lines in a spectral range
    spectral lines of gadolinium
    other properties
    natural occurrenceprimordial
    crystal structurehexagonal close-packed (hcp)
    hexagonal close packed crystal structure for gadolinium
    speed of sound thin rod2680 m/s (at 20 °c)
    thermal expansionα poly: 9.4 µm/(m·k) (at 100 °c)
    thermal conductivity10.6 w/(m·k)
    electrical resistivityα, poly: 1.310 µΩ·m
    magnetic orderingferromagnetic-paramagnetic transition at 293.4 k
    magnetic susceptibility+755,000.0·10−6 cm3/mol (300.6 k)[3]
    young's modulusα form: 54.8 gpa
    shear modulusα form: 21.8 gpa
    bulk modulusα form: 37.9 gpa
    poisson ratioα form: 0.259
    vickers hardness510–950 mpa
    cas number7440-54-2
    history
    namingafter the mineral gadolinite (itself named after johan gadolin)
    discoveryjean charles galissard de marignac (1880)
    first isolationlecoq de boisbaudran (1886)
    main isotopes of gadolinium
    iso­tope abun­dance half-life (t1/2) decay mode pro­duct
    148gd syn 75 y α 144sm
    150gd syn 1.8×106 y α 146sm
    152gd 0.20% 1.08×1014 y α 148sm
    154gd 2.18% stable
    155gd 14.80% stable
    156gd 20.47% stable
    157gd 15.65% stable
    158gd 24.84% stable
    160gd 21.86% stable
    category category: gadolinium
    | references

    gadolinium is a chemical element with the symbol gd and atomic number 64. gadolinium is a silvery-white metal when oxidation is removed. it is only slightly malleable and is a ductile rare-earth element. gadolinium reacts with atmospheric oxygen or moisture slowly to form a black coating. gadolinium below its curie point of 20 °c (68 °f) is ferromagnetic, with an attraction to a magnetic field higher than that of nickel. above this temperature it is the most paramagnetic element. it is found in nature only in an oxidized form. when separated, it usually has impurities of the other rare-earths because of their similar chemical properties.

    gadolinium was discovered in 1880 by jean charles de marignac, who detected its oxide by using spectroscopy. it is named after the mineral gadolinite, one of the minerals in which gadolinium is found, itself named for the chemist johan gadolin. pure gadolinium was first isolated by the chemist paul emile lecoq de boisbaudran around 1886.

    gadolinium possesses unusual metallurgical properties, to the extent that as little as 1% of gadolinium can significantly improve the workability and resistance to oxidation at high temperatures of iron, chromium, and related metals. gadolinium as a metal or a salt absorbs neutrons and is, therefore, used sometimes for shielding in neutron radiography and in nuclear reactors.

    like most of the rare earths, gadolinium forms trivalent ions with fluorescent properties, and salts of gadolinium(iii) are used as phosphors in various applications.

    the kinds of gadolinium(iii) ions occurring in water-soluble salts are toxic to mammals. however, chelated gadolinium(iii) compounds are far less toxic because they carry gadolinium(iii) through the kidneys and out of the body before the free ion can be released into the tissues. because of its paramagnetic properties, solutions of chelated organic gadolinium complexes are used as intravenously administered gadolinium-based mri contrast agents in medical magnetic resonance imaging.

  • characteristics
  • history
  • occurrence
  • production
  • applications
  • biological role
  • safety
  • references
  • external links

Gadolinium, 64Gd
Gadolinium-4.jpg
Gadolinium
Pronunciationm/ (LIN-ee-əm)
Appearancesilvery white
Standard atomic weight Ar, std(Gd)157.25(3)[1]
Gadolinium in the periodic table
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson


Gd

Cm
europiumgadoliniumterbium
Atomic number (Z)64
Groupgroup n/a
Periodperiod 6
Blockf-block
Element category  Lanthanide
Electron configuration[Xe] 4f7 5d1 6s2
Electrons per shell2, 8, 18, 25, 9, 2
Physical properties
Phase at STPsolid
Melting point1585 K ​(1312 °C, ​2394 °F)
Boiling point3273 K ​(3000 °C, ​5432 °F)
Density (near r.t.)7.90 g/cm3
when liquid (at m.p.)7.4 g/cm3
Heat of fusion10.05 kJ/mol
Heat of vaporization301.3 kJ/mol
Molar heat capacity37.03 J/(mol·K)
Vapor pressure (calculated)
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 1836 2028 2267 2573 2976 3535
Atomic properties
Oxidation states0,[2] +1, +2, +3 (a mildly basic oxide)
ElectronegativityPauling scale: 1.20
Ionization energies
  • 1st: 593.4 kJ/mol
  • 2nd: 1170 kJ/mol
  • 3rd: 1990 kJ/mol
Atomic radiusempirical: 180 pm
Covalent radius196±6 pm
Color lines in a spectral range
Spectral lines of gadolinium
Other properties
Natural occurrenceprimordial
Crystal structurehexagonal close-packed (hcp)
Hexagonal close packed crystal structure for gadolinium
Speed of sound thin rod2680 m/s (at 20 °C)
Thermal expansionα poly: 9.4 µm/(m·K) (at 100 °C)
Thermal conductivity10.6 W/(m·K)
Electrical resistivityα, poly: 1.310 µΩ·m
Magnetic orderingferromagnetic-paramagnetic transition at 293.4 K
Magnetic susceptibility+755,000.0·10−6 cm3/mol (300.6 K)[3]
Young's modulusα form: 54.8 GPa
Shear modulusα form: 21.8 GPa
Bulk modulusα form: 37.9 GPa
Poisson ratioα form: 0.259
Vickers hardness510–950 MPa
CAS Number7440-54-2
History
Namingafter the mineral Gadolinite (itself named after Johan Gadolin)
DiscoveryJean Charles Galissard de Marignac (1880)
First isolationLecoq de Boisbaudran (1886)
Main isotopes of gadolinium
Iso­tope Abun­dance Half-life (t1/2) Decay mode Pro­duct
148Gd syn 75 y α 144Sm
150Gd syn 1.8×106 y α 146Sm
152Gd 0.20% 1.08×1014 y α 148Sm
154Gd 2.18% stable
155Gd 14.80% stable
156Gd 20.47% stable
157Gd 15.65% stable
158Gd 24.84% stable
160Gd 21.86% stable
Category Category: Gadolinium
| references

Gadolinium is a chemical element with the symbol Gd and atomic number 64. Gadolinium is a silvery-white metal when oxidation is removed. It is only slightly malleable and is a ductile rare-earth element. Gadolinium reacts with atmospheric oxygen or moisture slowly to form a black coating. Gadolinium below its Curie point of 20 °C (68 °F) is ferromagnetic, with an attraction to a magnetic field higher than that of nickel. Above this temperature it is the most paramagnetic element. It is found in nature only in an oxidized form. When separated, it usually has impurities of the other rare-earths because of their similar chemical properties.

Gadolinium was discovered in 1880 by Jean Charles de Marignac, who detected its oxide by using spectroscopy. It is named after the mineral gadolinite, one of the minerals in which gadolinium is found, itself named for the chemist Johan Gadolin. Pure gadolinium was first isolated by the chemist Paul Emile Lecoq de Boisbaudran around 1886.

Gadolinium possesses unusual metallurgical properties, to the extent that as little as 1% of gadolinium can significantly improve the workability and resistance to oxidation at high temperatures of iron, chromium, and related metals. Gadolinium as a metal or a salt absorbs neutrons and is, therefore, used sometimes for shielding in neutron radiography and in nuclear reactors.

Like most of the rare earths, gadolinium forms trivalent ions with fluorescent properties, and salts of gadolinium(III) are used as phosphors in various applications.

The kinds of gadolinium(III) ions occurring in water-soluble salts are toxic to mammals. However, chelated gadolinium(III) compounds are far less toxic because they carry gadolinium(III) through the kidneys and out of the body before the free ion can be released into the tissues. Because of its paramagnetic properties, solutions of chelated organic gadolinium complexes are used as intravenously administered gadolinium-based MRI contrast agents in medical magnetic resonance imaging.