Difference between revisions of "Germanium"

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{{Infobox element
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<!-- General properties -->
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|name=Germanium
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|symbol=Ge
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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=α-Ge, β-Ge
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|appearance=Lustrous gray
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<!-- Periodic table -->
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|above=[[Silicon|Si]]
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|below=[[Tin|Sn]]
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|left=[[Gallium]]
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|right=[[Arsenic]]
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|number=32
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|atomic mass=72.630(8)
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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=14
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|group ref=
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|group comment=(carbon group)
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|period=4
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|period ref=
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|period comment=
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|block=p
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|block ref=
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|block comment=
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|electron configuration=[Ar] 3d<sup>10</sup> 4s<sup>2</sup> 4p<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, 4
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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=Lustrous 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=1211.40
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|melting point C=938.25
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|melting point F=​1720.85
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|melting point ref=
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|melting point comment=
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|boiling point K=3106
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|boiling point C=2833
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|boiling point F=​5131
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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=5.323
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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 gpcm3nrt 3 comment=
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|density gpcm3mp=5.60
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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 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=36.94
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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=334
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|heat vaporization ref=
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|heat vaporization comment=
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|heat capacity=23.222
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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=1644
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|vapor pressure 10=1814
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|vapor pressure 100=2023
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|vapor pressure 1 k=2287
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|vapor pressure 10 k=2633
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|vapor pressure 100 k=3104
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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='''4''', 3, '''2''', 1, 0, −1, −2, −3, '''−4'''
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|oxidation states ref=
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|oxidation states comment=(an amphoteric oxide)
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|electronegativity=2.01
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|electronegativity ref=
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|electronegativity comment=
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|ionization energy 1=762
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|ionization energy 1 ref=
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|ionization energy 1 comment=
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|ionization energy 2=1537.5
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|ionization energy 2 ref=
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|ionization energy 2 comment=
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|ionization energy 3=3302.1
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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=122
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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=122
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|covalent radius ref=
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|covalent radius comment=
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|Van der Waals radius=211
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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-centered diamond-cubic
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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=5400
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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=6.0
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|thermal expansion ref=
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|thermal expansion comment=
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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=60.2
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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 diffusivity=
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|electrical resistivity=
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|electrical resistivity comment=
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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=1
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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 comment=
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|magnetic ordering=
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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=103
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|Young's modulus ref=
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|Young's modulus comment=
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|Shear modulus=41
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|Shear modulus ref=
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|Shear modulus comment=
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|Bulk modulus=75
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|Bulk modulus ref=
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|Bulk modulus comment=
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|Poisson ratio=0.26
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|Poisson ratio ref=
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|Poisson ratio comment=
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|Mohs hardness=6.0
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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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|Vickers hardness=
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|Vickers hardness comment=
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|Brinell hardness=
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|Brinell hardness ref=
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|Brinell hardness comment=
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|CAS number=7440-56-4
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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 Germany, homeland of the discoverer
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|predicted by=Dmitri Mendeleev
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|prediction date ref=
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|prediction date=1871
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|discovered by=Clemens Winkler
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|discovery date ref=
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|discovery date=1886
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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 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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}}
 
'''Germanium''' is a chemical element with symbol '''Ge''' and atomic number 32. It is a metalloid.
 
'''Germanium''' is a chemical element with symbol '''Ge''' and atomic number 32. It is a metalloid.
  

Revision as of 21:04, 15 October 2017

Germanium,  32Ge
General properties
Name, symbol Germanium, Ge
Allotropes α-Ge, β-Ge
Appearance Lustrous gray
Germanium in the periodic table
Si
↑
Ge
↓
Sn
Gallium ← Germanium → Arsenic
Atomic number 32
Standard atomic weight (Ar) 72.630(8)
Group, block (carbon group); p-block
Period period 4
Electron configuration [Ar] 3d10 4s2 4p2
per shell
 2, 8, 18, 4
Physical properties
Lustrous gray
Phase Solid
Melting point 1211.40 K ​(938.25 °C, ​​1720.85 °F)
Boiling point 3106 K ​(2833 °C, ​​5131 °F)
Density near r.t. 5.323 g/cm3
when liquid, at  5.60 g/cm3
Heat of fusion 36.94 kJ/mol
Heat of 334 kJ/mol
Molar heat capacity 23.222 J/(mol·K)
 pressure
Atomic properties
Oxidation states 4, 3, 2, 1, 0, −1, −2, −3, −4 ​(an amphoteric oxide)
Electronegativity Pauling scale: 2.01
energies 1st: 762 kJ/mol
2nd: 1537.5 kJ/mol
3rd: 3302.1 kJ/mol
Atomic radius empirical: 122 pm
Covalent radius 122 pm
Van der Waals radius 211 pm
Miscellanea
Crystal structure ​Face-centered diamond-cubic
Speed of sound thin rod 5400 m/s (at 20 °C)
Thermal expansion 6.0 µm/(m·K)
Thermal conductivity 60.2 W/(m·K)
Electrical resistivity 1 Ω·m (at 20 °C)
Young's modulus 103 GPa
Shear modulus 41 GPa
Bulk modulus 75 GPa
Poisson ratio 0.26
Mohs hardness 6.0
CAS Registry Number 7440-56-4
History
Naming After Germany, homeland of the discoverer
Prediction Dmitri Mendeleev (1871)
Discovery Clemens Winkler (1886)
· references

Germanium is a chemical element with symbol Ge and atomic number 32. It is a metalloid.

Properties

Chemical

Elemental germanium is stable in air, and slowly oxidizes to GeO2 at 250 °C. Germanium is insoluble in dilute acids and alkalis, but reacts slowly with concentrated sulfuric acid and violently with molten alkalis to produce germanates ([GeO3]2−).

Germanium halides hydrolyze in water or moist air.

Physical

Germanium is a brittle, silvery-white, semi-metallic element. It posses two allotrope forms:

  • α-germanium: the form at standard conditions. It has a metallic luster and a diamond cubic crystal structure.
  • β-germanium: forms at pressures above 120 kbar. It posses the same structure as β-tin.

Extremely pure germanium will spontaneously extrude very long screw dislocations. This is the primary reason why old transistors fail.

Along with antimony, bismuth, gallium, silicon and water, it is one of the few substances that expands as it solidifies. Germanium is a semiconductor.

Availability

Germanium can be found in very old transistors and diodes, albeit the amount is small.

Pure germanium can be purchased from Metallium, at $11/g. It is very easy to find extremely pure germanium, as it is used in certain semiconductors.

Preparation

Elemental germanium can be prepared by reducing germanium dioxide (germania) with hydrogen.

GeO2 + H2 → Ge + H2O

This reaction requires high temperatures.

Germanium is less reactive than silicon, so carbon can also be used as a reducing agent.

GeO2 + C → Ge + CO2

Unlike in the case of silicon, this reduction will yield only a small quantity of carbide.

Projects

Handling

Safety

Pure germanium has low toxicity, however its compounds have different biological effects. Inorganic germanium compounds tend to accumulate inside the body and will cause health related problems. Organic germanium compounds have been shown to be less toxic and some even have beneficial properties.

Storage

Germanium reacts very slowly in air to produce a thin protective layer of germania. No special storage is required.

Disposal

Germanium is present only in traces in nature. Germania is inert so it does not pose environmental hazard, and may be dumped in the trash. Inorganic germanium compounds should be converted to germania before discarding or recycling.

References

Relevant Sciencemadness threads

Retrieved from "https://www.sciencemadness.org/smwiki/index.php?title=Germanium&oldid=7770"