Praseodymium is a chemical element that haes the seembol Pr an atomic nummer 59. Praseodymium is a saft, sillery, malleable an ductile metal in the lanthanide group. It is too reactive tae be foond in native furm, an when airtificially prepared, it slowly develops a green oxide coatin.

Praseodymium, 59Pr
Template:Infobox element/symbol-to-top-image/alt
Praseodymium
Pronunciation/ˌprziˈdɪmiəm/ (PRAY-zee-oh-DIM-ee-əm[1])
Appearancegrayish white
Standard atomic weight Ar, std(Pr)140.90766(1)[2]
Praseodymium in the periodic cairt
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 Airn Cobalt Nickel Capper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Siller (element) 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 Gowd Mercur (element) Thallium Leid (element) 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 Ununtrium Flerovium Ununpentium Livermorium Ununseptium Ununoctium
-

Pr

Pa
ceriumpraseodymiumneodymium
Atomic nummer (Z)59
Groupgroup n/a
Periodperiod 6
Blockf-block
Element category  Lanthanide
Electron confeeguration[Xe] 4f3 6s2
Electrons per shell2, 8, 18, 21, 8, 2
Pheesical properties
Phase at STPsolit
Meltin pynt1208 K ​(935 °C, ​1715 °F)
Bylin pynt3793 K ​(3520 °C, ​6368 °F)
Density (near r.t.)6.77 g/cm3
when liquid (at m.p.)6.50 g/cm3
Heat o fusion6.89 kJ/mol
Heat o vapourisation331 kJ/mol
Molar heat capacity27.20 J/(mol·K)
Vapour pressur
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
Atomic radiusempirical: 182 pm
Covalent radius203±7 pm
Colour lines in a spectral range
Spectral lines o praseodymium
Ither properties
Naitural occurrenceprimordial
Creestal structurhexagonal
Hexagonal creestal structur for praseodymium
Speed o soond thin rod2280 m/s (at 20 °C)
Thermal expansion(r.t.) (α, poly) 6.7 µm/(m·K)
Thermal conductivity12.5 W/(m·K)
Electrical resistivity(r.t.) (α, poly)
0.700 µ Ω·m
Magnetic orderinparamagnetic[5]
Young's modulus(α form) 37.3 GPa
Shear modulus(α form) 14.8 GPa
Bulk modulus(α form) 28.8 GPa
Poisson ratio(α form) 0.281
Vickers haurdness400 MPa
Brinell haurdness481 MPa
CAS Nummer7440-10-0
History
DiskiveryCarl Auer von Welsbach (1885)
Main isotopes o praseodymium
Iso­tope Abun­dance Hauf-life (t1/2) Decay mode Pro­duct
141Pr 100% - (SF)
142Pr syn 19.12 h β 142Nd
ε 142Ce
143Pr syn 13.57 d β 143Nd
Decay modes in parentheses hae been predictit, but hae nae yet been observed
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ReferencesEedit

  1. "praseodymium". Oxford English Dictionary (3rd ed.). Oxford University Press. September 2005. (Subscription or UK public leebrar membership required.)
  2. Meija, Juris; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–91. doi:10.1515/pac-2015-0305.
  3. Yttrium and all lanthanides except Ce, Pm, Eu, Tm, Yb have been observed in the oxidation state 0 in bis(1,3,5-tri-t-butylbenzene) complexes, see Cloke, F. Geoffrey N. (1993). "Zero Oxidation State Compounds of Scandium, Yttrium, and the Lanthanides". Chem. Soc. Rev. 22: 17–24. doi:10.1039/CS9932200017.
  4. Chen, Xin; et al. (2019-12-13). "Lanthanides with Unusually Low Oxidation States in the PrB3– and PrB4– Boride Clusters". Inorganic Chemistry. 58 (1): 411–418. doi:10.1021/acs.inorgchem.8b02572. PMID 30543295.
  5. M. Jackson "Magnetism of Rare Earth" The IRM quarterly col. 10, No. 3, p. 1, 2000
  6. "praseodymium". Oxford English Dictionary (3rd ed.). Oxford University Press. September 2005. (Subscription or UK public leebrar membership required.)