Difference between revisions of "Osmium"

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'''Osmium''' is the chemical element with symbol '''Os '''and atomic number 76.
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{{Infobox element
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<!-- General properties -->
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|name=Osmium
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|symbol=Os
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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, bluish cast
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<!-- Periodic table -->
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|above=[[Ruthenium|Ru]]
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|below=Hs
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|left=[[Rhenium]]
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|right=[[Iridium]]
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|number=76
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|atomic mass=190.23(3)
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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= 8
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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=d
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|block ref=
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|block comment=
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|electron configuration=[Xe] 4f<sup>14</sup> 5d<sup>6</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, 32, 14, 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 with bluish cast
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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=3306
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|melting point C=3033
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|melting point F=​5491
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|melting point ref=
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|melting point comment=
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|boiling point K=5285
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|boiling point C=5012
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|boiling point F=9054
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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=22.59
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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=20
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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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|triple point 2 ref=
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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=31
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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=378
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|heat vaporization ref=
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|heat vaporization comment=
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|heat capacity=24.7
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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=3160
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|vapor pressure 10=3423
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|vapor pressure 100=3751
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|vapor pressure 1 k=4148
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|vapor pressure 10 k=4638
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|vapor pressure 100 k=5256
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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=8, 7, 6, 5, '''4''', 3, 2, 1, 0, −1, −2, −4
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|oxidation states ref=
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|oxidation states comment=(a mildly acidic oxide)
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|electronegativity=2.2
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|electronegativity ref=
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|electronegativity comment=
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|ionization energy 1=840
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|ionization energy 1 ref=
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|ionization energy 1 comment=
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|ionization energy 2=1600
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|ionization energy 2 ref=
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|ionization energy 2 comment=
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|ionization energy 3=
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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=135
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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=144±4
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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=4940
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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=5.1
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|thermal expansion at 25 ref=
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|thermal expansion at 25 comment=
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|thermal conductivity=87.6
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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 comment=
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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=81.2·10<sup>-9</sup>
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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=
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|Young's modulus ref=
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|Young's modulus comment=
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|Shear modulus=222
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|Shear modulus ref=
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|Shear modulus comment=
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|Bulk modulus=462
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|Bulk modulus ref=
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|Bulk modulus comment=
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|Poisson ratio=0.25
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|Poisson ratio ref=
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|Poisson ratio comment=
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|Mohs hardness=7.0
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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=
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|Vickers hardness ref=
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|Vickers hardness comment=
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|Brinell hardness=3490–4000
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|Brinell hardness ref=
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|Brinell hardness comment=
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|CAS number=7440-04-2
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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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|discovered by=
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|discovery date=
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|first isolation by=
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|first isolation date=
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|discovery and first isolation by=Smithson Tennant (1803)
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|named by=
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|named date=
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|history comment label=
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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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}}
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'''Osmium''' is the chemical element with symbol '''Os''' and atomic number 76.
  
 
== Properties ==
 
== Properties ==
 
=== Chemical properties ===
 
=== Chemical properties ===
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Osmium forms compounds with oxidation state from '''-2''' to '''8'''. It is slightly attacked by aqua regia, and by fuming nitric acid, and it is attacked by molten hydroxides. It forms the toxic [[osmium tetroxide]] ('''OsO<sub>4</sub>'''), the most common compound with '''+8''' oxidation state, in contact with air. A lower oxide, [[osmium dioxide]], is known. It forms coordination complexes easily.
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Osmium forms compounds with oxidation state from '''-2''' to '''8'''. It is slightly attacked by [[aqua regia]], and by fuming [[nitric acid]], and it is attacked by molten hydroxides. It forms the toxic [[osmium tetroxide]] (OsO<sub>4</sub>), the most common compound with '''+8''' oxidation state, in contact with air, though bulk metal is much less prone to forming the oxide than the powder. A lower oxide, [[osmium dioxide]], is known. It forms coordination complexes easily.
  
 
=== Physical properties ===
 
=== Physical properties ===
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Osmium is a hard, brittle, white-bluish transition metal and usually is found in traces in platinum ores. It is the densest element known, with a density of 22.6 g/cm<sup>3</sup>, slightly denser than [[iridium]]. It's almost twice as dense as lead. It melts at 3033 ºC, which makes it unfeasible for the amateur chemist to cast.
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Osmium is a hard, brittle, white-bluish transition metal and usually is found in traces in platinum ores. It is the densest non-radioactive element known, with a density of 22.6 g/cm<sup>3</sup> (22.59 g/cm<sup>3</sup> according to most sources), slightly denser than [[iridium]]. Osmium is almost twice as dense as [[lead]]. It has a very high melting point of 3033 ºC, which makes it unfeasible for the amateur chemist to cast.
  
 
== Availability ==
 
== Availability ==
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It is one of the rarest elements so it is quite expensive. It can be bought online from Metallium.
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Osmium is one of the rarest elements so it is quite expensive. It can be bought online from Metallium and sometimes from eBay.
  
 
==Projects==
 
==Projects==
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*Osmium tetroxide synthesis (Dangerous! Toxic!)
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*[[Osmium tetroxide]] synthesis (Dangerous! Toxic!)
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*Organoosmium compounds
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*Organo-osmium compounds
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*[[Element collecting]]
  
 
==Handling==
 
==Handling==
 
===Safety===
 
===Safety===
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Osmium metal poses very little toxicity as it does not react with most reagents. Osmium powder, however, will slowly oxidise in air to form osmium tetroxide, which is toxic and a powerful oxidant. Osmium powder is also pyrophoric. The bulk metal, however, is safe to keep in air.
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Osmium metal poses very little toxicity as it does not react with most reagents. Osmium powder, however, will slowly oxidize in air to form osmium tetroxide, which is toxic and a powerful oxidant. Osmium powder is also known to be pyrophoric. The bulk metal, however, is safe to keep in air.
  
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===Stprage===
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===Storage===
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Bulk osmium does not require any special storage. Osmium powder should be kept in closed containers, in a well ventilated area, preferable under a gas other than air (such as carbon dioxide).
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Bulk osmium does not require any special storage. Osmium powder should be kept in closed containers, in a well ventilated area, preferable under a gas other than air (such as carbon dioxide, nitrogen, argon, etc.).
  
 
===Disposal===
 
===Disposal===
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Due to osmium's high price, it's best to try and recycle it as much possible.
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Due to osmium's high price, it's best to try and recycle it as much as possible.
  
 
==References==
 
==References==
 
<references/>
 
<references/>
 
===Relevant Sciencemadness threads===
 
===Relevant Sciencemadness threads===
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*[http://www.sciencemadness.org/talk/viewthread.php?tid=41135 OSMIUM]
  
 
[[Category:Elements]]
 
[[Category:Elements]]
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[[Category:Precious metals]]
 
[[Category:Precious metals]]
 
[[Category:Inert chemicals]]
 
[[Category:Inert chemicals]]
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[[Category:Noble metals]]

Latest revision as of 16:43, 2 November 2022

Osmium,  76Os
General properties
Name, symbol Osmium, Os
Appearance Silvery, bluish cast
Osmium in the periodic table
Ru
↑
Os
↓
Hs
Rhenium ← Osmium → Iridium
Atomic number 76
Standard atomic weight (Ar) 190.23(3)
Group, block , d-block
Period period 6
Electron configuration [Xe] 4f14 5d6 6s2
per shell
 2, 8, 18, 32, 14, 2
Physical properties
Silvery with bluish cast
Phase Solid
Melting point 3306 K ​(3033 °C, ​​5491 °F)
Boiling point 5285 K ​(5012 °C, ​9054 °F)
Density near r.t. 22.59 g/cm3
when liquid, at  20 g/cm3
Heat of fusion 31 kJ/mol
Heat of 378 kJ/mol
Molar heat capacity 24.7 J/(mol·K)
 pressure
Atomic properties
Oxidation states 8, 7, 6, 5, 4, 3, 2, 1, 0, −1, −2, −4 ​(a mildly acidic oxide)
Electronegativity Pauling scale: 2.2
energies 1st: 840 kJ/mol
2nd: 1600 kJ/mol
Atomic radius empirical: 135 pm
Covalent radius 144±4 pm
Miscellanea
Crystal structure ​Hexagonal close-packed (hcp)
Speed of sound thin rod 4940 m/s (at 20 °C)
Thermal expansion 5.1 µm/(m·K) (at 25 °C)
Thermal conductivity 87.6 W/(m·K)
Electrical resistivity 81.2·10-9 Ω·m (at 0 °C)
Magnetic ordering Paramagnetic
Shear modulus 222 GPa
Bulk modulus 462 GPa
Poisson ratio 0.25
Mohs hardness 7.0
Brinell hardness 3490–4000 MPa
CAS Registry Number 7440-04-2
Discovery and first isolation Smithson Tennant (1803)
· references

Osmium is the chemical element with symbol Os and atomic number 76.

Properties

Chemical properties

Osmium forms compounds with oxidation state from -2 to 8. It is slightly attacked by aqua regia, and by fuming nitric acid, and it is attacked by molten hydroxides. It forms the toxic osmium tetroxide (OsO4), the most common compound with +8 oxidation state, in contact with air, though bulk metal is much less prone to forming the oxide than the powder. A lower oxide, osmium dioxide, is known. It forms coordination complexes easily.

Physical properties

Osmium is a hard, brittle, white-bluish transition metal and usually is found in traces in platinum ores. It is the densest non-radioactive element known, with a density of 22.6 g/cm3 (22.59 g/cm3 according to most sources), slightly denser than iridium. Osmium is almost twice as dense as lead. It has a very high melting point of 3033 ºC, which makes it unfeasible for the amateur chemist to cast.

Availability

Osmium is one of the rarest elements so it is quite expensive. It can be bought online from Metallium and sometimes from eBay.

Projects

Handling

Safety

Osmium metal poses very little toxicity as it does not react with most reagents. Osmium powder, however, will slowly oxidize in air to form osmium tetroxide, which is toxic and a powerful oxidant. Osmium powder is also known to be pyrophoric. The bulk metal, however, is safe to keep in air.

Storage

Bulk osmium does not require any special storage. Osmium powder should be kept in closed containers, in a well ventilated area, preferable under a gas other than air (such as carbon dioxide, nitrogen, argon, etc.).

Disposal

Due to osmium's high price, it's best to try and recycle it as much as possible.

References

Relevant Sciencemadness threads

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