Difference between revisions of "Cerium"

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'''Cerium''' is a chemical element with symbol '''Ce''' and atomic number 58. It is one of the most abundant rare earth metals, one of the easiest to separate, and one of the easiest to purchase. It is notable by its high propensity for sparking when struck, making it an ideal material for firestarters in the alloys [[ferrocerium]] and [[mischmetal]].
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{{Infobox element
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<!-- General properties -->
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|name=Cerium
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|symbol=Ce
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|pronounce=
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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=Silvery white
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<!-- Periodic table -->
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|above=-
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|below=[[Thorium|Th]]
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|left=[[Lanthanum]]
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|right=[[Praseodymium]]
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|number=58
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|atomic mass=140.116(1)
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|atomic mass 2=
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|atomic mass comment=
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|series=
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|series color=
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|group=
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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>1</sup> 5d<sup>1</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, 19, 9, 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=Silvery-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=1068
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|melting point C=795
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|melting point F=​1463
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|melting point ref=
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|melting point comment=
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|boiling point K=3716​
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|boiling point C=3443
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|boiling point F=6229
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|boiling point comment=
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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 gplstp comment=
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|density gpcm3nrt=6.77
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|density gpcm3nrt ref=
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|density gpcm3nrt 3=
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|density gpcm3mp=6.55
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|density gpcm3bp=
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|density gpcm3bp ref=
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|density gpcm3bp comment=
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|molar volume=
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|molar volume unit =
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|molar volume comment=
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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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|critical point K=
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|critical point MPa=
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|critical point ref=
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|critical point comment=
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|heat fusion=5.46
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|heat fusion ref=
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|heat fusion 2=
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|heat vaporization=398
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|heat vaporization ref=
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|heat vaporization comment=
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|heat capacity=26.94
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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=1992
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|vapor pressure 10=2194
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|vapor pressure 100=2442
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|vapor pressure 1 k=2754
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|vapor pressure 10 k=3159
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|vapor pressure 100 k=3705
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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 2 comment=
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<!-- Atomic properties -->
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|atomic properties comment=
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|oxidation states='''4''', '''3''', 2, 1
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|oxidation states ref=
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|oxidation states comment=(a mildly basic oxide)
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|electronegativity=1.12
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|electronegativity ref=
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|electronegativity comment=
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|ionization energy 1=534.4
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|ionization energy 1 ref=
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|ionization energy 1 comment=
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|ionization energy 2=1050
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|ionization energy 2 ref=
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|ionization energy 2 comment=
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|ionization energy 3=1949
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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=181.8
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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=204±9
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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=''β-Ce''<br>Double hexagonal close-packed (dhcp)<br>''γ-Ce''<br>Face-centered cubic (fcc)
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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=2,100
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|speed of sound rod at 20 ref=
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|speed of sound rod at 20 comment=
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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=6.3
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|thermal expansion ref=
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|thermal expansion comment=(γ, 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=11.3
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|thermal conductivity ref=
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|thermal conductivity 2=
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|electrical resistivity at 0=
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|electrical resistivity at 0 ref=
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|electrical resistivity at 0 comment=
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|electrical resistivity at 20=828·10<sup>-9</sup>
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|electrical resistivity at 20 ref=
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|electrical resistivity at 20 comment=(β, poly)
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|band gap=
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|band gap ref=
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|band gap comment=
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|Curie point K=
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|Curie point ref=
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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=33.6
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|Young's modulus ref=
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|Young's modulus comment=(γ-Ce)
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|Shear modulus=13.5
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|Shear modulus ref=
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|Shear modulus comment=(γ-Ce)
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|Bulk modulus=21.5
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|Bulk modulus ref=
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|Bulk modulus comment=(γ-Ce)
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|Poisson ratio=0.24
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|Poisson ratio ref=
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|Poisson ratio comment=(γ-Ce)
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|Mohs hardness=2.5
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|Mohs hardness ref=
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|Mohs hardness comment=
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|Mohs hardness 2=
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|Mohs hardness 2 comment=
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|Vickers hardness=210–470
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|Vickers hardness ref=
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|Vickers hardness comment=
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|Brinell hardness=186–412
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|Brinell hardness ref=
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|Brinell hardness comment=
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|CAS number=7440-45-1
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|CAS number ref=
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|CAS number comment=
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<!-- History -->
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|naming=After dwarf planet Ceres, itself named after Roman deity of agriculture Ceres
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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=Martin Heinrich Klaproth, Jöns Jakob Berzelius, Wilhelm Hisinger
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|discovery date ref=
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|discovery date=1803
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|first isolation by=Carl Gustaf Mosander
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|first isolation date ref=
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|first isolation date=1838
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|discovery and first isolation by=
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|named by=
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|named date=
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<!-- Isotopes -->
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|isotopes=
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|engvar=
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}}
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'''Cerium''' is a chemical element with symbol '''Ce''' and atomic number 58. It is one of the most abundant [[rare earth metal]]s, one of the easiest to separate, and one of the easiest to purchase. It is notable by its high propensity for sparking when struck, making it an ideal material for firestarters in the alloys [[ferrocerium]] and [[mischmetal]].
  
 
==Properties==
 
==Properties==
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==Availability==
 
==Availability==
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Cerium can be purchased from [http://www.mcssl.com/store/gallium-source/031---cerium-metal GalliumSource]. 30 g costs US$55. It can also be found in ferrocerium firestarters, though due to its high reactivity, the extraction process is complex and required reduction with a more reactive metal, such as calcium.
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Cerium can be purchased from [http://www.mcssl.com/store/gallium-source/031---cerium-metal GalliumSource]. 30 g costs US$55. It can also be found in ferrocerium firestarters, though due to its high reactivity, the extraction process is complex and required reduction with a more reactive metal, such as [[calcium]].
  
 
==Preparation==
 
==Preparation==

Revision as of 22:08, 14 July 2019

Cerium,  58Ce
General properties
Name, symbol Cerium, Ce
Appearance Silvery white
Cerium in the periodic table
-
↑
Ce
↓
Th
Lanthanum ← Cerium → Praseodymium
Atomic number 58
Standard atomic weight (Ar) 140.116(1)
Group, block , f-block
Period period 6
Electron configuration [Xe] 4f1 5d1 6s2
per shell
 2, 8, 18, 19, 9, 2
Physical properties
Silvery-white
Phase Solid
Melting point 1068 K ​(795 °C, ​​1463 °F)
Boiling point 3716​ K ​(3443 °C, ​6229 °F)
Density near r.t. 6.77 g/cm3
when liquid, at  6.55 g/cm3
Heat of fusion 5.46 kJ/mol
Heat of 398 kJ/mol
Molar heat capacity 26.94 J/(mol·K)
 pressure
Atomic properties
Oxidation states 4, 3, 2, 1 ​(a mildly basic oxide)
Electronegativity Pauling scale: 1.12
energies 1st: 534.4 kJ/mol
2nd: 1050 kJ/mol
3rd: 1949 kJ/mol
Atomic radius empirical: 181.8 pm
Covalent radius 204±9 pm
Miscellanea
Crystal structure ​β-Ce
Double hexagonal close-packed (dhcp)
γ-Ce
Face-centered cubic (fcc)
Speed of sound thin rod 2,100 m/s (at 20 °C)
Thermal expansion 6.3 µm/(m·K) (γ, poly)
Thermal conductivity 11.3 W/(m·K)
Electrical resistivity 828·10-9 Ω·m (at 20 °C) (β, poly)
Magnetic ordering Paramagnetic
Young's modulus 33.6 GPa (γ-Ce)
Shear modulus 13.5 GPa (γ-Ce)
Bulk modulus 21.5 GPa (γ-Ce)
Poisson ratio 0.24 (γ-Ce)
Mohs hardness 2.5
Vickers hardness 210–470 MPa
Brinell hardness 186–412 MPa
CAS Registry Number 7440-45-1
History
Naming After dwarf planet Ceres, itself named after Roman deity of agriculture Ceres
Discovery Martin Heinrich Klaproth, Jöns Jakob Berzelius, Wilhelm Hisinger (1803)
First isolation Carl Gustaf Mosander (1838)
· references

Cerium is a chemical element with symbol Ce and atomic number 58. It is one of the most abundant rare earth metals, one of the easiest to separate, and one of the easiest to purchase. It is notable by its high propensity for sparking when struck, making it an ideal material for firestarters in the alloys ferrocerium and mischmetal.

Properties

Chemical

Cerium metal tarnishes slowly in air and burns readily at 150 °C to form cerium(IV) oxide:

Ce + O2 → CeO2

Cerium reacts with all halogens to form trihalides. Cerium will slowly react with water.

Cerium is notable among the lanthanides due to the existence of a cerium(III) (cerous) state and cerium(IV) (ceric) state. While cerous compounds are usually colorless or white, and form colorless complexes as well, cerric salts usually present a yellow, orange, or red coloration. Cerium(IV) sulfate is a strong oxidizing agent which can oxidize hydrogen peroxide to oxygen and water. Ceric ammonium sulfate is a commonly available from lab suppliers.

Physical

Cerium is a grey silvery metal, soft, and both malleable and ductile. Cerium has the third-longest liquid range of any element, after thorium and uranium: 2648 °C (795 °C to 3443 °C). It sparks readily when cut, ground, or struck.

Availability

Cerium can be purchased from GalliumSource. 30 g costs US$55. It can also be found in ferrocerium firestarters, though due to its high reactivity, the extraction process is complex and required reduction with a more reactive metal, such as calcium.

Preparation

Cerium can be prepared by reducing its oxide with lithium or calcium, but this is impractical compared to simply purchasing a sample of the metal.

Projects

  • Ferrocerium
  • Use as an oxidizer

Safety and storage

Safety

Cerium metal is not known to be toxic, but it is a relatively large fire hazard due to its tendency to spark. Even sanding or filing a sample by hand can cause a significant amount of sparking and ignite flammable objects. These sparks are quite large and may include small globs of burning metal. Cerium fires should never be put out with water as it may cause a hydrogen explosion. Cerium and mischmetal fires have a distinct smell that has both a metallic and smoky quality.

Storage

Cerium corrodes relatively easily and should be stored in an airtight container under mineral oil or argon.

Disposal

Cerium compounds present little toxicity and can be safely disposed of. However, due to the high price of lanthanides, it's better to try to recycle them.

References

Relevant Sciencemadness threads

Retrieved from "https://www.sciencemadness.org/smwiki/index.php?title=Cerium&oldid=11740"