Difference between revisions of "Thorium"

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{{Infobox element
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<!-- General properties -->
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|name=Thorium
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|symbol=Th
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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=Silvery-grey, often black tarnish
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<!-- Periodic table -->
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|above=[[Cerium|Ce]]
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|below=Uqq
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|left=[[Actinium]]
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|right=[[Protactinium]]
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|number=90
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|atomic mass=232.0377(4)
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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=Actinides
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|series color=
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|group=
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|group ref=
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|group comment=n/a
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|period=7
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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=[Rn] 6d<sup>2</sup> 7s<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, 32, 18, 10, 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-gray
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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=2023
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|melting point C=1750
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|melting point F=3182
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|melting point ref=
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|melting point comment=
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|boiling point K=5061
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|boiling point C=4788
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|boiling point F=8650
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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=11.7
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|density gpcm3mp=
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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 2 comment=
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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=13.81
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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 fusion 2 comment=
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|heat vaporization=514
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|heat vaporization ref=
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|heat vaporization comment=
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|heat capacity=26.23
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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=2633
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|vapor pressure 10=2907
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|vapor pressure 100=3248
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|vapor pressure 1 k=3683
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|vapor pressure 10 k=4259
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|vapor pressure 100 k=5055
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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 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='''4''', 3, 2, 1
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|oxidation states ref=
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|oxidation states comment=(a weakly basic oxide)
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|electronegativity=1.3
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|electronegativity ref=
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|electronegativity comment=
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|ionization energy 1=587
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|ionization energy 1 ref=
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|ionization energy 1 comment=
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|ionization energy 2=1110
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|ionization energy 2 ref=
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|ionization energy 2 comment=
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|ionization energy 3=1930
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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=179.8
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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=206±6
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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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|Van der Waals radius ref=
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|Van der Waals radius comment=
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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=Face-centred 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=2490
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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=
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|thermal expansion ref=
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|thermal expansion comment=
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|thermal expansion at 25=11
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|thermal expansion at 25 ref=
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|thermal expansion at 25 comment=
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|thermal conductivity=54
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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=
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|electrical resistivity=
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|electrical resistivity unit prefix=
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|electrical resistivity ref=
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|electrical resistivity comment=
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|electrical resistivity at 0=157
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|electrical resistivity at 0 ref=
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|electrical resistivity at 20=
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|electrical resistivity at 20 ref=
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|band gap=
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|band gap ref=
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|Curie point K=
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|Curie point ref=
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|Curie point comment=
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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=79
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|Young's modulus ref=
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|Young's modulus comment=
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|Shear modulus=31
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|Shear modulus ref=
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|Shear modulus comment=
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|Bulk modulus=54
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|Bulk modulus ref=
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|Bulk modulus comment=
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|Poisson ratio=0.27
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|Poisson ratio ref=
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|Poisson ratio comment=
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|Mohs hardness=3.0
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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 ref=
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|Mohs hardness 2 comment=
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|Vickers hardness=295–685
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|Vickers hardness ref=
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|Vickers hardness comment=
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|Brinell hardness=390–1500
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|Brinell hardness ref=
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|Brinell hardness comment=
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|CAS number=7440-29-1
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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 Thor, the Norse god of thunder
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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= Jöns Jakob Berzelius
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|discovery date ref=
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|discovery date=1829
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|first isolation by=
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|first isolation date ref=
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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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|isotopes comment=
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|engvar=
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}}
 
'''Thorium''' is a chemical element with the symbol '''Th''' and atomic number 90.
 
'''Thorium''' is a chemical element with the symbol '''Th''' and atomic number 90.
  
 
==Properties==
 
==Properties==
 
===Chemical===
 
===Chemical===
−
Thorium is a highly reactive metal. At room temperature, thorium is slowly attacked by water, but does not readily dissolve in most common acids, the exception being hydrochloric acid. It will dissolve in concentrated nitric acid containing a small amount of catalytic fluoride or fluorosilicate ions. At high temperatures, it is easily attacked by [[oxygen]], [[hydrogen]], [[nitrogen]], the halogens, and [[sulfur]]. Finely divided thorium is highly pyrophoric. Thorium burns with a bright white flame in air.
+
Thorium is a highly reactive metal. At room temperature, thorium is slowly attacked by water but does not readily dissolve in most common acids, the exception being hydrochloric acid. It will dissolve in concentrated nitric acid containing a small amount of catalytic fluoride or fluorosilicate ions. At high temperatures, it is easily attacked by [[oxygen]], [[hydrogen]], [[nitrogen]], the halogens, and [[sulfur]]. Finely divided thorium is highly pyrophoric. Thorium burns with a bright white flame in the air.
  
 
===Physical===
 
===Physical===
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:ThO<sub>2</sub> + 2 Ca → 2 CaO + Th
 
:ThO<sub>2</sub> + 2 Ca → 2 CaO + Th
 +
 +
Dissolving TIG welding rods in acids or alkali is difficult, as tungsten is very resistant to most reagents, and bulk metal is even more inert. However, one can successfully dissolve them in concentrated H<sub>2</sub>O<sub>2</sub>, which forms tungstic acid and  ThO<sub>2</sub>.
  
 
==Projects==
 
==Projects==
Line 33: Line 307:
  
 
===Disposal===
 
===Disposal===
−
Thorium and its compounds compounds, are toxic, and it is recommended to avoid dumping the compounds in the environment and instead should be taken to waste disposal facilities.
+
Thorium and its compounds, are toxic, and it is recommended to avoid dumping the compounds in the environment and instead should be taken to waste disposal facilities.
  
−
If the thorium was extracted from its natural ore that was taken from an area where the said ore can be easily collected, it's not entirely a bad idea to dispose of the ore wastes as well as thorium compounds residues in the said area, as the ore area is already naturally contaminated and the amount of ore waste is the same as the one you originally picked it up.
+
If the thorium was extracted from its natural ore that was taken from an area where the said ore can be easily collected, it's not entirely a bad idea to dispose of the ore wastes as well as thorium compounds residues in the said area, as the said area is already naturally contaminated and radioactive and the amount of ore waste is (almost) the same as the one you originally picked it up.
  
 
==References==
 
==References==
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*[http://www.sciencemadness.org/talk/viewthread.php?tid=29927 The trials and tribulations of Thorium production]
 
*[http://www.sciencemadness.org/talk/viewthread.php?tid=29927 The trials and tribulations of Thorium production]
 
*[http://www.sciencemadness.org/talk/viewthread.php?tid=11275 Thorium Separation From TIG Electrodes]
 
*[http://www.sciencemadness.org/talk/viewthread.php?tid=11275 Thorium Separation From TIG Electrodes]
 +
*[https://www.sciencemadness.org/whisper/viewthread.php?tid=158808 Thorium from monazite sand]
  
 
[[Category:Elements]]
 
[[Category:Elements]]
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[[Category:Radioactives]]
 
[[Category:Radioactives]]
 
[[Category:Heavy metal toxicants]]
 
[[Category:Heavy metal toxicants]]
−
[[Category:Pyrophoric]]
+
[[Category:Pyrophoric materials]]
 
[[Category:F-block]]
 
[[Category:F-block]]

Latest revision as of 20:50, 23 October 2022

Thorium,  90Th
General properties
Name, symbol Thorium, Th
Appearance Silvery-grey, often black tarnish
Thorium in the periodic table
Ce
↑
Th
↓
Uqq
Actinium ← Thorium → Protactinium
Atomic number 90
Standard atomic weight (Ar) 232.0377(4)
Element category Actinides
Group, block n/a; f-block
Period period 7
Electron configuration [Rn] 6d2 7s2
per shell
 2, 8, 18, 32, 18, 10, 2
Physical properties
Silvery-gray
Phase Solid
Melting point 2023 K ​(1750 °C, ​3182 °F)
Boiling point 5061 K ​(4788 °C, ​8650 °F)
Density near r.t. 11.7 g/cm3
Heat of fusion 13.81 kJ/mol
Heat of 514 kJ/mol
Molar heat capacity 26.23 J/(mol·K)
 pressure
Atomic properties
Oxidation states 4, 3, 2, 1 ​(a weakly basic oxide)
Electronegativity Pauling scale: 1.3
energies 1st: 587 kJ/mol
2nd: 1110 kJ/mol
3rd: 1930 kJ/mol
Atomic radius empirical: 179.8 pm
Covalent radius 206±6 pm
Miscellanea
Crystal structure ​Face-centred cubic (fcc)
Speed of sound thin rod 2490 m/s (at 20 °C)
Thermal expansion 11 µm/(m·K) (at 25 °C)
Thermal conductivity 54 W/(m·K)
Electrical resistivity 157 Ω·m (at 0 °C)
Magnetic ordering Paramagnetic
Young's modulus 79 GPa
Shear modulus 31 GPa
Bulk modulus 54 GPa
Poisson ratio 0.27
Mohs hardness 3.0
Vickers hardness 295–685 MPa
Brinell hardness 390–1500 MPa
CAS Registry Number 7440-29-1
History
Naming After Thor, the Norse god of thunder
Discovery Jöns Jakob Berzelius (1829)
· references

Thorium is a chemical element with the symbol Th and atomic number 90.

Properties

Chemical

Thorium is a highly reactive metal. At room temperature, thorium is slowly attacked by water but does not readily dissolve in most common acids, the exception being hydrochloric acid. It will dissolve in concentrated nitric acid containing a small amount of catalytic fluoride or fluorosilicate ions. At high temperatures, it is easily attacked by oxygen, hydrogen, nitrogen, the halogens, and sulfur. Finely divided thorium is highly pyrophoric. Thorium burns with a bright white flame in the air.

Physical

Thorium is a soft, paramagnetic, bright silvery radioactive actinide metal. Pure thorium is soft, very ductile. Because thorium melts at 1750 °C and boils at 4788 °C, it has one of the widest liquid range of all metals.

Availability

Thorium was available in the past as thorium dioxide in gas mantles. Certain heat resistant ceramics contain thoria. Small amounts of thorium are added in TIG welding rods. Old gas mantles can contain amounts of thorium dioxide.

The acquisition of pure metal is problematic, as there are almost no companies that will sell very small samples to individuals. Element collector Max Whitby explained in a YT video that there are extremely few companies that will sell small samples of thorium, even chemical lab suppliers. He also discovered that shipping it outside requires a heavy-duty license for radioactive materials, as he discovered when he was visited by authorities.

Isolation

Metallic thorium can be extracted by reducing thorium dioxide with calcium in an inert atmosphere:

ThO2 + 2 Ca → 2 CaO + Th

Dissolving TIG welding rods in acids or alkali is difficult, as tungsten is very resistant to most reagents, and bulk metal is even more inert. However, one can successfully dissolve them in concentrated H2O2, which forms tungstic acid and ThO2.

Projects

  • Thorium halides
  • Make thorium dioxide
  • Firestarters

Handling

Safety

Thorium is highly reactive and pyrophoric. It is only mildly radioactive (232Th has a half-life of 14.05 billion years and is alpha radioactive), the radiation is too weak to penetrate the skin. Soluble thorium compounds are toxic and should be handled with proper protection.

Bulk thorium is difficult to ignite, but finely divided metal is highly pyrophoric.

Storage

As thorium will slowly react with the air, it should be stored under oil or under an inert atmosphere, in a container. Sealing it is not necessary. Being weak radioactive, thorium does not require radiation shielding (the storage container walls will effectively absorb the weak alpha radiation).

Disposal

Thorium and its compounds, are toxic, and it is recommended to avoid dumping the compounds in the environment and instead should be taken to waste disposal facilities.

If the thorium was extracted from its natural ore that was taken from an area where the said ore can be easily collected, it's not entirely a bad idea to dispose of the ore wastes as well as thorium compounds residues in the said area, as the said area is already naturally contaminated and radioactive and the amount of ore waste is (almost) the same as the one you originally picked it up.

References

Relevant Sciencemadness threads

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