Praseodymium

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Praseodymium
59Pr
-

Pr

Pa
ceriumpraseodymiumneodymium
Appearance
grayish white
General properties
Name, seembol, nummer praseodymium, Pr, 59
Pronunciation /przəˈdɪmiəm/
pray-zee-ə-DIM-ee-əm[1]
Element category lanthanide
Group, period, block n/a, 6, f
Staundart atomic wicht 140.90766(2)
Electron confeeguration [Xe] 4f3 6s2
2, 8, 18, 21, 8, 2
Electron shells of praseodymium (2, 8, 18, 21, 8, 2)
History
Discovery Carl Auer von Welsbach (1885)
Physical properties
Phase solid
Density (near r.t.) 6.77 g·cm−3
Liquid density at m.p. 6.50 g·cm−3
Meltin pynt 1208 K, 935 °C, 1715 °F
Boilin pynt 3793 K, 3520 °C, 6368 °F
Heat o fusion 6.89 kJ·mol−1
Heat o vaporization 331 kJ·mol−1
Molar heat capacity 27.20 J·mol−1·K−1
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 states 4, 3, 2 (mildly basic oxide)
Electronegativity 1.13 (Pauling scale)
Ionization energies 1st: 527 kJ·mol−1
2nd: 1020 kJ·mol−1
3rd: 2086 kJ·mol−1
Atomic radius 182 pm
Covalent radius 203±7 pm
Miscellanea
Crystal structure hexagonal
Praseodymium has a hexagonal crystal structure
Magnetic orderin paramagnetic[2]
Electrical resistivity (r.t.) (α, poly)
0.700 µΩ·m
Thermal conductivity 12.5 W·m−1·K−1
Thermal expansion (r.t.) (α, poly) 6.7 µm/(m·K)
Speed of sound (thin rod) (20 °C) 2280 m·s−1
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 hairdness 400 MPa
Brinell hairdness 481 MPa
CAS registry nummer 7440-10-0
Most stable isotopes
Main article: Isotopes o praseodymium
iso NA hauf-life DM DE (MeV) DP
141Pr 100% - (SF) <48.450
142Pr syn 19.12 h β 2.162 142Nd
ε 0.745 142Ce
143Pr syn 13.57 d β 0.934 143Nd
Decay modes in parentheses hae been predictit, but hae nae yet been observed
· r

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.

References[eedit | eedit soorce]

  1. "praseodymium". Oxford English Dictionary (3rd ed.). Oxford University Press. 2001. 
  2. M. Jackson "Magnetism of Rare Earth" The IRM quarterly col. 10, No. 3, p. 1, 2000