Praseodymium

  • praseodymium, 59pr
    praseodymium.jpg
    praseodymium
    pronunciationm/[1] (dim-ee-əm)
    appearancegrayish white
    standard atomic weight ar, std(pr)140.90766(1)[2]
    praseodymium 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


    pr

    pa
    ceriumpraseodymiumneodymium
    atomic number (z)59
    groupgroup n/a
    periodperiod 6
    blockf-block
    element category  lanthanide
    electron configuration[xe] 4f3 6s2
    electrons per shell2, 8, 18, 21, 8, 2
    physical properties
    phase at stpsolid
    melting point1208 k ​(935 °c, ​1715 °f)
    boiling point3403 k ​(3130 °c, ​5666 °f)
    density (near r.t.)6.77 g/cm3
    when liquid (at m.p.)6.50 g/cm3
    heat of fusion6.89 kj/mol
    heat of vaporization331 kj/mol
    molar heat capacity27.20 j/(mol·k)
    vapor pressure
    p (pa) 1 10 100 1 k 10 k 100 k
    at t (k) 1771 1973 (2227) (2571) (3054) (3779)
    atomic properties
    oxidation states0,[3] +1,[4] +2, +3, +4, +5 (a mildly basic oxide)
    electronegativitypauling scale: 1.13
    ionization energies
    • 1st: 527 kj/mol
    • 2nd: 1020 kj/mol
    • 3rd: 2086 kj/mol
    atomic radiusempirical: 182 pm
    covalent radius203±7 pm
    color lines in a spectral range
    spectral lines of praseodymium
    other properties
    natural occurrenceprimordial
    crystal structuredouble hexagonal close-packed (dhcp)
    double hexagonal close packed crystal structure for praseodymium
    speed of sound thin rod2280 m/s (at 20 °c)
    thermal expansionα, poly: 6.7 µm/(m·k) (at r.t.)
    thermal conductivity12.5 w/(m·k)
    electrical resistivityα, poly: 0.700 µΩ·m (at r.t.)
    magnetic orderingparamagnetic[5]
    magnetic susceptibility+5010.0·10−6 cm3/mol (293 k)[6]
    young's modulusα form: 37.3 gpa
    shear modulusα form: 14.8 gpa
    bulk modulusα form: 28.8 gpa
    poisson ratioα form: 0.281
    vickers hardness250–745 mpa
    brinell hardness250–640 mpa
    cas number7440-10-0
    history
    discoverycarl auer von welsbach (1885)
    main isotopes of praseodymium
    iso­tope abun­dance half-life (t1/2) decay mode pro­duct
    141pr 100% stable
    142pr syn 19.12 h β 142nd
    ε 142ce
    143pr syn 13.57 d β 143nd
    category category: praseodymium
    | references

    praseodymium is a chemical element with the symbol pr and atomic number 59. it is the third member of the lanthanide series and is traditionally considered to be one of the rare-earth metals. praseodymium is a soft, silvery, malleable and ductile metal, valued for its magnetic, electrical, chemical, and optical properties. it is too reactive to be found in native form, and pure praseodymium metal slowly develops a green oxide coating when exposed to air.

    praseodymium always occurs naturally together with the other rare-earth metals. it is the fourth most common rare-earth element, making up 9.1 parts per million of the earth's crust, an abundance similar to that of boron. in 1841, swedish chemist carl gustav mosander extracted a rare-earth oxide residue he called didymium from a residue he called "lanthana", in turn separated from cerium salts. in 1885, the austrian chemist baron carl auer von welsbach separated didymium into two elements that gave salts of different colours, which he named praseodymium and neodymium. the name praseodymium comes from the greek prasinos (πράσινος), meaning "green", and didymos (δίδυμος), "twin".

    like most rare-earth elements, praseodymium most readily forms the +3 oxidation state, which is the only stable state in aqueous solution, although the +4 oxidation state is known in some solid compounds and, uniquely among the lanthanides, the +5 oxidation state is attainable in matrix-isolation conditions. aqueous praseodymium ions are yellowish-green, and similarly praseodymium results in various shades of yellow-green when incorporated into glasses. many of praseodymium's industrial uses involve its ability to filter yellow light from light sources.

  • characteristics
  • chemistry
  • history
  • occurrence and production
  • applications
  • biological role and precautions
  • references
  • bibliography
  • further reading
  • external links

Praseodymium, 59Pr
Praseodymium.jpg
Praseodymium
Pronunciationm/[1] (DIM-ee-əm)
Appearancegrayish white
Standard atomic weight Ar, std(Pr)140.90766(1)[2]
Praseodymium 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


Pr

Pa
ceriumpraseodymiumneodymium
Atomic number (Z)59
Groupgroup n/a
Periodperiod 6
Blockf-block
Element category  Lanthanide
Electron configuration[Xe] 4f3 6s2
Electrons per shell2, 8, 18, 21, 8, 2
Physical properties
Phase at STPsolid
Melting point1208 K ​(935 °C, ​1715 °F)
Boiling point3403 K ​(3130 °C, ​5666 °F)
Density (near r.t.)6.77 g/cm3
when liquid (at m.p.)6.50 g/cm3
Heat of fusion6.89 kJ/mol
Heat of vaporization331 kJ/mol
Molar heat capacity27.20 J/(mol·K)
Vapor pressure
P (Pa) 1 10 100 1 k 10 k 100 k
at T (K) 1771 1973 (2227) (2571) (3054) (3779)
Atomic properties
Oxidation states0,[3] +1,[4] +2, +3, +4, +5 (a mildly basic oxide)
ElectronegativityPauling scale: 1.13
Ionization energies
  • 1st: 527 kJ/mol
  • 2nd: 1020 kJ/mol
  • 3rd: 2086 kJ/mol
Atomic radiusempirical: 182 pm
Covalent radius203±7 pm
Color lines in a spectral range
Spectral lines of praseodymium
Other properties
Natural occurrenceprimordial
Crystal structuredouble hexagonal close-packed (dhcp)
Double hexagonal close packed crystal structure for praseodymium
Speed of sound thin rod2280 m/s (at 20 °C)
Thermal expansionα, poly: 6.7 µm/(m·K) (at r.t.)
Thermal conductivity12.5 W/(m·K)
Electrical resistivityα, poly: 0.700 µΩ·m (at r.t.)
Magnetic orderingparamagnetic[5]
Magnetic susceptibility+5010.0·10−6 cm3/mol (293 K)[6]
Young's modulusα form: 37.3 GPa
Shear modulusα form: 14.8 GPa
Bulk modulusα form: 28.8 GPa
Poisson ratioα form: 0.281
Vickers hardness250–745 MPa
Brinell hardness250–640 MPa
CAS Number7440-10-0
History
DiscoveryCarl Auer von Welsbach (1885)
Main isotopes of praseodymium
Iso­tope Abun­dance Half-life (t1/2) Decay mode Pro­duct
141Pr 100% stable
142Pr syn 19.12 h β 142Nd
ε 142Ce
143Pr syn 13.57 d β 143Nd
Category Category: Praseodymium
| references

Praseodymium is a chemical element with the symbol Pr and atomic number 59. It is the third member of the lanthanide series and is traditionally considered to be one of the rare-earth metals. Praseodymium is a soft, silvery, malleable and ductile metal, valued for its magnetic, electrical, chemical, and optical properties. It is too reactive to be found in native form, and pure praseodymium metal slowly develops a green oxide coating when exposed to air.

Praseodymium always occurs naturally together with the other rare-earth metals. It is the fourth most common rare-earth element, making up 9.1 parts per million of the Earth's crust, an abundance similar to that of boron. In 1841, Swedish chemist Carl Gustav Mosander extracted a rare-earth oxide residue he called didymium from a residue he called "lanthana", in turn separated from cerium salts. In 1885, the Austrian chemist Baron Carl Auer von Welsbach separated didymium into two elements that gave salts of different colours, which he named praseodymium and neodymium. The name praseodymium comes from the Greek prasinos (πράσινος), meaning "green", and didymos (δίδυμος), "twin".

Like most rare-earth elements, praseodymium most readily forms the +3 oxidation state, which is the only stable state in aqueous solution, although the +4 oxidation state is known in some solid compounds and, uniquely among the lanthanides, the +5 oxidation state is attainable in matrix-isolation conditions. Aqueous praseodymium ions are yellowish-green, and similarly praseodymium results in various shades of yellow-green when incorporated into glasses. Many of praseodymium's industrial uses involve its ability to filter yellow light from light sources.