Difference between revisions of "Holmium"

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{{Infobox element
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|image name=Holmium.jpg
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|image name 2=
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<!-- General properties -->
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|name=Holmium
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|symbol=Ho
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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=Soft, silvery white metal
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<!-- Periodic table -->
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|above=-
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|below=Es
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|left=[[Dysprosium]]
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|right=[[Erbium]]
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|number=67
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|atomic mass=164.93033(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=n\a
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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>11</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, 29, 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=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=1734
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|melting point C=1461
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|melting point F=2662
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|melting point ref=
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|melting point comment=
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|boiling point K=2873
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|boiling point C=2600
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|boiling point F=4712
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|boiling point ref=
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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 ref=
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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=8.79
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|density gpcm3nrt ref=
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|density gpcm3nrt comment=
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|density gpcm3nrt 2=
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|density gpcm3nrt 3=
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|density gpcm3mp=8.34
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|density gpcm3mp ref=
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|density gpcm3mp comment=
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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 ref=
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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 ref=
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|triple point comment=
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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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|critical point ref=
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|critical point comment=
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|heat fusion=17
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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=251
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|heat vaporization ref=
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|heat vaporization comment=
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|heat capacity=27.15
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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=1432
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|vapor pressure 10=1584
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|vapor pressure 100=(1775)
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|vapor pressure 1 k=(2040)
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|vapor pressure 10 k=(2410)
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|vapor pressure 100 k=(2964)
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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='''3''', 2, 1
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|oxidation states ref=
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|oxidation states comment=(a basic oxide)
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|electronegativity=1.23
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|electronegativity ref=
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|electronegativity comment=
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|ionization energy 1=581
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|ionization energy 1 ref=
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|ionization energy 1 comment=
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|ionization energy 2=1140
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|ionization energy 2 ref=
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|ionization energy 2 comment=
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|ionization energy 3=2204
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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=176
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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=192±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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|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=Hexagonal close-packed (hcp)
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|crystal structure 2=
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|crystal structure 2 prefix=
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|crystal structure 2 ref=
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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=2760
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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=11.2
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|thermal expansion ref=
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|thermal expansion comment=(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=16.2
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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 conductivity 2 ref=
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|thermal conductivity 2 comment=
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|thermal diffusivity=
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|thermal diffusivity ref=
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|thermal diffusivity comment=
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|electrical resistivity=8.14·10<sup>-7</sup>
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|electrical resistivity unit prefix=
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|electrical resistivity ref=
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|electrical resistivity comment=(poly)
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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=
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|electrical resistivity at 20 ref=
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|electrical resistivity at 20 comment=
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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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|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=64.8
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|Young's modulus ref=
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|Young's modulus comment=
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|Shear modulus=26.3
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|Shear modulus ref=
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|Shear modulus comment=
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|Bulk modulus=40.2
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|Bulk modulus ref=
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|Bulk modulus comment=
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|Poisson ratio=0.231
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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 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=410–600
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|Vickers hardness ref=
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|Vickers hardness comment=
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|Brinell hardness=500–1250
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|Brinell hardness ref=
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|Brinell hardness comment=
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|CAS number=7440-60-0
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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=Jacques-Louis Soret
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|discovery date ref=
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|discovery date=1878
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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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|named date=
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|history comment=
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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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}}
 
'''Holmium''' is a lanthanide with the atomic number 67 and the symbol '''Ho'''. It is a gray metal that is reactive and slightly magnetic at room temperature. Holmium is difficult to find and somewhat expensive, but has some interesting properties regarding its magnetism and narrow absorption bands.
 
'''Holmium''' is a lanthanide with the atomic number 67 and the symbol '''Ho'''. It is a gray metal that is reactive and slightly magnetic at room temperature. Holmium is difficult to find and somewhat expensive, but has some interesting properties regarding its magnetism and narrow absorption bands.
  
 
==Properties==  
 
==Properties==  
 
===Physical properties===
 
===Physical properties===
−
As a lanthanide, holmium resembles is neighboring elements strongly. It is paramagnetic, enough to be visibly lifted by a [[neodymium magnet]]. Its trivalent salts show dramatic color changes depending on the light source: they appear yellow in natural daylight, but vividly pink under compact fluorescent lighting, and very slightly pink under tube lighting.
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As a lanthanide, holmium resembles is neighboring elements strongly. It is paramagnetic, enough to be visibly lifted by a [[Neodymium iron boron magnet|neodymium magnet]]. Its trivalent salts show dramatic color changes depending on the light source: they appear yellow in natural daylight, but vividly pink under compact fluorescent lighting, and very slightly pink under tube lighting.
  
 
===Chemical properties===  
 
===Chemical properties===  
−
Holmium is a strong reducing agent and will readily react with weak oxidizers. It burns in air with a yellow [https://www.flickr.com/photos/37388341@N00/2696039566/in/photostream/] or green[https://www.flickr.com/photos/37388341@N00/2381429226/]flame to form holmium oxide. (The green color is likely the true color of burning holmium; the yellow color may be black-body radiation from the products.) Holmium is almost exclusively trivalent, and it is extremely difficult to reduce or oxidize holmium salts. It also reacts with the halogens to form colorful halides, which have the same color-changing properties under different light sources.
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Holmium is a strong reducing agent and will readily react with weak oxidizers. It burns in air with a [https://www.flickr.com/photos/37388341@N00/2696039566/in/photostream/ yellow] or [https://www.flickr.com/photos/37388341@N00/2381429226/ green] flame to form holmium oxide. (The green color is likely the true color of burning holmium; the yellow color may be black-body radiation from the products.) Holmium is almost exclusively trivalent, and it is extremely difficult to reduce or oxidize holmium salts. It also reacts with the halogens to form colorful halides, which have the same color-changing properties under different light sources.
  
 
Holmium carbonate may form a soluble complex, but can be broken by addition of [[hydrogen peroxide]].
 
Holmium carbonate may form a soluble complex, but can be broken by addition of [[hydrogen peroxide]].
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Holmium is more common than [[iodine]] on Earth, but it is very hard to find. For a lanthanides, it is cheaper than some other metals. One source for holmium, as well as other rare earth metals, is Metallium. It is sold in 5 gram and 50 gram sizes, as well as rods, ampoules, and coins. Holmium and its compounds are occasionally sold on eBay as well.
 
Holmium is more common than [[iodine]] on Earth, but it is very hard to find. For a lanthanides, it is cheaper than some other metals. One source for holmium, as well as other rare earth metals, is Metallium. It is sold in 5 gram and 50 gram sizes, as well as rods, ampoules, and coins. Holmium and its compounds are occasionally sold on eBay as well.
  
−
==Projects==  
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==Isolation==
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Holmium can be obtained by reducing holmium salts, like holmium(III) chloride, with [[calcium]] metal in a thermite-like reaction.
 +
 
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==Projects==
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*Make holmium compounds
 
*Color changing crystals.
 
*Color changing crystals.
 
*Magnet polepieces?
 
*Magnet polepieces?
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*Element collecting
  
 
==Safety==  
 
==Safety==  
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===Flammability===  
 
===Flammability===  
−
Small pieces of holmium metal or powder are flammable. Class D [[fire extinguishers]] should be readily available when working with large amounts of holmium near an open flame. Water should never be used to extinguish burning holmium, as it will aggravate the flame.
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Small pieces of holmium metal or powder are flammable. Class D [[fire extinguisher]]s should be readily available when working with large amounts of holmium near an open flame. Water should never be used to extinguish burning holmium, as it will aggravate the flame.
 +
 
 +
===Disposal===
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Due to holmium's rarity, it's best to recycle it.
  
 
==References==  
 
==References==  
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[[Category:Elements]]
 
[[Category:Elements]]
 
[[Category:Metals]]
 
[[Category:Metals]]
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[[Category:Rare earth metals]]
 
[[Category:Lanthanides]]
 
[[Category:Lanthanides]]
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[[Category:Reducing agents]]
 
[[Category:Materials unstable in acidic solution]]
 
[[Category:Materials unstable in acidic solution]]
 
[[Category:Materials that react with water]]
 
[[Category:Materials that react with water]]
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[[Category:Air-sensitive materials]]
 
[[Category:F-block]]
 
[[Category:F-block]]

Latest revision as of 21:44, 27 March 2019

Holmium,  67Ho
Holmium.jpg
General properties
Name, symbol Holmium, Ho
Appearance Soft, silvery white metal
Holmium in the periodic table
-
↑
Ho
↓
Es
Dysprosium ← Holmium → Erbium
Atomic number 67
Standard atomic weight (Ar) 164.93033(2)
Group, block , f-block
Period period 6
Electron configuration [Xe] 4f11 6s2
per shell
 2, 8, 18, 29, 8, 2
Physical properties
Silvery-white
Phase Solid
Melting point 1734 K ​(1461 °C, ​2662 °F)
Boiling point 2873 K ​(2600 °C, ​4712 °F)
Density near r.t. 8.79 g/cm3
when liquid, at  8.34 g/cm3
Heat of fusion 17 kJ/mol
Heat of 251 kJ/mol
Molar heat capacity 27.15 J/(mol·K)
 pressure
Atomic properties
Oxidation states 3, 2, 1 ​(a basic oxide)
Electronegativity Pauling scale: 1.23
energies 1st: 581 kJ/mol
2nd: 1140 kJ/mol
3rd: 2204 kJ/mol
Atomic radius empirical: 176 pm
Covalent radius 192±7 pm
Miscellanea
Crystal structure ​Hexagonal close-packed (hcp)
Speed of sound thin rod 2760 m/s (at 20 °C)
Thermal expansion 11.2 µm/(m·K) (poly)
Thermal conductivity 16.2 W/(m·K)
Electrical resistivity 8.14·10-7 Ω·m (poly)
Magnetic ordering Paramagnetic
Young's modulus 64.8 GPa
Shear modulus 26.3 GPa
Bulk modulus 40.2 GPa
Poisson ratio 0.231
Vickers hardness 410–600 MPa
Brinell hardness 500–1250 MPa
CAS Registry Number 7440-60-0
History
Discovery Jacques-Louis Soret (1878)
· references

Holmium is a lanthanide with the atomic number 67 and the symbol Ho. It is a gray metal that is reactive and slightly magnetic at room temperature. Holmium is difficult to find and somewhat expensive, but has some interesting properties regarding its magnetism and narrow absorption bands.

Properties

Physical properties

As a lanthanide, holmium resembles is neighboring elements strongly. It is paramagnetic, enough to be visibly lifted by a neodymium magnet. Its trivalent salts show dramatic color changes depending on the light source: they appear yellow in natural daylight, but vividly pink under compact fluorescent lighting, and very slightly pink under tube lighting.

Chemical properties

Holmium is a strong reducing agent and will readily react with weak oxidizers. It burns in air with a yellow or green flame to form holmium oxide. (The green color is likely the true color of burning holmium; the yellow color may be black-body radiation from the products.) Holmium is almost exclusively trivalent, and it is extremely difficult to reduce or oxidize holmium salts. It also reacts with the halogens to form colorful halides, which have the same color-changing properties under different light sources.

Holmium carbonate may form a soluble complex, but can be broken by addition of hydrogen peroxide.

Holmium trifluoroacetate and holmium trifluoromethanesulfonate (triflate) are relatively recently discovered catalysts for organic reactions. Even though they are Lewis acids, they do not hydrolyze readily and can be used in numerous solvents. Other lanthanide triflates have been investigated for catalytic activity.

Availability

Holmium is more common than iodine on Earth, but it is very hard to find. For a lanthanides, it is cheaper than some other metals. One source for holmium, as well as other rare earth metals, is Metallium. It is sold in 5 gram and 50 gram sizes, as well as rods, ampoules, and coins. Holmium and its compounds are occasionally sold on eBay as well.

Isolation

Holmium can be obtained by reducing holmium salts, like holmium(III) chloride, with calcium metal in a thermite-like reaction.

Projects

  • Make holmium compounds
  • Color changing crystals.
  • Magnet polepieces?
  • Element collecting

Safety

Storage

Bulk holmium metal is stable in air indefinitely. As a powder or fine turnings, it may be extremely flammable, and should be kept away from ignition sources.

Toxicity

Holmium and its compounds have not been thoroughly investigated for toxicity, but no adverse effects have been reported from exposure.

Flammability

Small pieces of holmium metal or powder are flammable. Class D fire extinguishers should be readily available when working with large amounts of holmium near an open flame. Water should never be used to extinguish burning holmium, as it will aggravate the flame.

Disposal

Due to holmium's rarity, it's best to recycle it.

References

  • flickr.com/photos/37388341@N00/2696039566/in/photostream/
  • flickr.com/photos/37388341@N00/2381429226/

Relevant Sciencemadness threads

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