Difference between revisions of "Praseodymium"

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{{Infobox element
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<!-- General properties -->
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|name=Praseodymium
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|symbol=Pr
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|pronounce=
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|pronounce ref=
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|pronounce comment=
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|pronounce 2=
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|alt name=
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|alt names=
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|allotropes=
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|appearance=Gray-white
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<!-- Periodic table -->
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|above=
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|below=Pa
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|left=[[Cerium]]
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|right=[[Neodymium]]
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|number=59
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|atomic mass=140.90766(2)
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|atomic mass 2=
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|atomic mass ref=
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|atomic mass comment=
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|series=
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|series ref=
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|series comment=
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|series color=
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|group=
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|group ref=
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|group comment=
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|period=6
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|period ref=
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|period comment=
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|block=f
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|block ref=
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|block comment=
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|electron configuration=[Xe] 4f<sup>3</sup> 6s<sup>2</sup>
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|electron configuration ref=
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|electron configuration comment=
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|electrons per shell=2, 8, 18, 21, 8, 2
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|electrons per shell ref=
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|electrons per shell comment=
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<!-- Physical properties -->
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|physical properties comment=
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|color=Gray-white
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|phase=Solid
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|phase ref=
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|phase comment=
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|melting point K=1208
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|melting point C=935
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|melting point F=​1715
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|melting point ref=
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|melting point comment=
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|boiling point K=3403
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|boiling point C=3130
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|boiling point F=​5666
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|sublimation point K=
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|sublimation point C=
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|sublimation point F=
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|sublimation point comment=
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|density gplstp=
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|density gplstp ref=
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|density gpcm3nrt=6.77
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|density gpcm3mp=6.50
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|density gpcm3bp=
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|molar volume=
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|molar volume unit =
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|triple point K=
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|triple point kPa=
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|triple point K 2=
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|triple point kPa 2=
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|critical point K=
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|critical point MPa=
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|heat fusion=6.89
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|heat fusion ref=
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|heat fusion comment=
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|heat fusion 2=
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|heat fusion 2 ref=
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|heat vaporization=331
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|heat vaporization ref=
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|heat vaporization comment=
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|heat capacity=27.2
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|heat capacity ref=
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|heat capacity comment=
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|heat capacity 2=
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|heat capacity 2 ref=
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|heat capacity 2 comment=
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|vapor pressure 1=1771
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|vapor pressure 10=1973
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|vapor pressure 100=(2227)
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|vapor pressure 1 k=(2571)
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|vapor pressure 10 k=(3054)
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|vapor pressure 100 k=(3779)
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|vapor pressure ref=
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|vapor pressure comment=
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|vapor pressure 1 2=
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|vapor pressure 10 2=
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|vapor pressure 100 2=
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|vapor pressure 1 k 2=
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|vapor pressure 10 k 2=
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|vapor pressure 100 k 2=
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|vapor pressure 2 ref=
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|vapor pressure 2 comment=
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<!-- Atomic properties -->
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|atomic properties comment=
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|oxidation states=5, 4, '''3''', 2
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|oxidation states ref=
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|oxidation states comment=(a mildly basic oxide)
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|electronegativity=1.13
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|electronegativity ref=
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|electronegativity comment=
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|ionization energy 1=527
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|ionization energy 1 ref=
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|ionization energy 1 comment=
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|ionization energy 2=1020
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|ionization energy 2 ref=
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|ionization energy 2 comment=
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|ionization energy 3=2086
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|ionization energy 3 ref=
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|ionization energy 3 comment=
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|number of ionization energies=
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|ionization energy ref=
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|ionization energy comment=
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|atomic radius=182
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|atomic radius ref=
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|atomic radius comment=
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|atomic radius calculated=
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|atomic radius calculated ref=
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|atomic radius calculated comment=
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|covalent radius=203±7
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|covalent radius ref=
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|covalent radius comment=
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|Van der Waals radius=
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<!-- Miscellanea -->
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|crystal structure=
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|crystal structure prefix=
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|crystal structure ref=
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|crystal structure comment= Double hexagonal close-packed (dhcp)
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|crystal structure 2=
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|crystal structure 2 prefix=
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|crystal structure 2 comment=
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|speed of sound=
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|speed of sound ref=
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|speed of sound comment=
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|speed of sound rod at 20=2280
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|speed of sound rod at 20 ref=
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|speed of sound rod at r.t.=
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|speed of sound rod at r.t. ref=
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|speed of sound rod at r.t. comment=
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|thermal expansion=6.7
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|thermal expansion ref=
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|thermal expansion comment=(α, poly)
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|thermal expansion at 25=
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|thermal expansion at 25 ref=
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|thermal expansion at 25 comment=
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|thermal conductivity=12.5
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|thermal conductivity ref=
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|thermal conductivity comment=
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|thermal conductivity 2=
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|thermal diffusivity comment=
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|electrical resistivity=7·10<sup>-7</sup>
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|electrical resistivity comment=(α, poly)
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|electrical resistivity at 0=
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|electrical resistivity at 20=
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|band gap=
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|Curie point K=
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|magnetic ordering=Paramagnetic
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|magnetic ordering ref=
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|magnetic ordering comment=
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|tensile strength=
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|tensile strength ref=
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|tensile strength comment=
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|Young's modulus=37.3
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|Young's modulus ref=
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|Young's modulus comment=(α form)
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|Shear modulus=14.8
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|Shear modulus ref=
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|Shear modulus comment=(α form)
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|Bulk modulus=28.8
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|Bulk modulus ref=
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|Bulk modulus comment=(α form)
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|Poisson ratio=0.281
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|Poisson ratio ref=
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|Poisson ratio comment=
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|Mohs hardness=
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|Mohs hardness 2=
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|Mohs hardness 2 comment=
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|Vickers hardness=250–745
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|Vickers hardness ref=
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|Vickers hardness comment=
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|Brinell hardness=250–640
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|Brinell hardness ref=
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|Brinell hardness comment=
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|CAS number=7440-10-0
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|CAS number ref=
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|CAS number comment=
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<!-- History -->
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|naming=
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|predicted by=
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|prediction date ref=
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|prediction date=
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|discovered by=Carl Auer von Welsbach
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|discovery date ref=
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|discovery date=1885
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|first isolation by=
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|first isolation date=
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|discovery and first isolation by=
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|named by=
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<!-- Isotopes -->
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|isotopes=
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|engvar=
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}}
 
'''Praseodymium''' is a chemical element with the atomic number 59 and symbol '''Pr'''.
 
'''Praseodymium''' is a chemical element with the atomic number 59 and symbol '''Pr'''.
  

Revision as of 08:02, 21 October 2017

Praseodymium,  59Pr
General properties
Name, symbol Praseodymium, Pr
Appearance Gray-white
Praseodymium in the periodic table

↑
Pr
↓
Pa
Cerium ← Praseodymium → Neodymium
Atomic number 59
Standard atomic weight (Ar) 140.90766(2)
Group, block , f-block
Period period 6
Electron configuration [Xe] 4f3 6s2
per shell
 2, 8, 18, 21, 8, 2
Physical properties
Gray-white
Phase Solid
Melting point 1208 K ​(935 °C, ​​1715 °F)
Boiling point 3403 K ​(3130 °C, ​​5666 °F)
Density near r.t. 6.77 g/cm3
when liquid, at  6.50 g/cm3
Heat of fusion 6.89 kJ/mol
Heat of 331 kJ/mol
Molar heat capacity 27.2 J/(mol·K)
 pressure
Atomic properties
Oxidation states 5, 4, 3, 2 ​(a mildly basic oxide)
Electronegativity Pauling scale: 1.13
energies 1st: 527 kJ/mol
2nd: 1020 kJ/mol
3rd: 2086 kJ/mol
Atomic radius empirical: 182 pm
Covalent radius 203±7 pm
Miscellanea
Crystal structure ​Double hexagonal close-packed (dhcp)
Speed of sound thin rod 2280 m/s (at 20 °C)
Thermal expansion 6.7 µm/(m·K) (α, poly)
Thermal conductivity 12.5 W/(m·K)
Electrical resistivity 7·10-7 Ω·m (α, poly)
Magnetic ordering Paramagnetic
Young's modulus 37.3 GPa (α form)
Shear modulus 14.8 GPa (α form)
Bulk modulus 28.8 GPa (α form)
Poisson ratio 0.281
Vickers hardness 250–745 MPa
Brinell hardness 250–640 MPa
CAS Registry Number 7440-10-0
History
Discovery Carl Auer von Welsbach (1885)
· references

Praseodymium is a chemical element with the atomic number 59 and symbol Pr.

Properties

Chemical

Praseodymium metal tarnishes slowly in air and burns readily at 150 °C to form praseodymium(III,IV) oxide:

12 Pr + 11 O2 → 2 Pr6O11

It is somewhat more resistant to corrosion in air than most lanthanides, such as europium, lanthanum, cerium, or neodymium. It will slowly build-up a green oxide coating that spalls off when exposed to air, exposing more metal to oxidation.

Physical

Praseodymium is a silvery, soft, malleable, and ductile lanthanide metal. It will slowly oxidize in air, giving the metal a greenish aspect. It melts at 935 °C and boils at 3130 °C. Its density is 6.77 g/cm3.

Availability

Praseodymium is sold by Metallium and can also be purchased from Ebay.

Preparation

Reducing praseodymium salts with a reactive metal such as calcium or magnesium yields metallic praseodymium.

Projects

  • Praseodymium yellow-green glass
  • Make didymium
  • Make PrNi5 alloy

Handling

Safety

Like all lanthanides, praseodymium has low to moderate toxicity. It has no known biological role.

Storage

In closed bottles or ampoules, away from moisture or corrosive vapors.

Disposal

Best to try to recycle it.

References

Relevant Sciencemadness threads

Retrieved from "https://www.sciencemadness.org/smwiki/index.php?title=Praseodymium&oldid=7787"