Difference between revisions of "Silicon"

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[[File:Silicon2.jpg|thumb|220x220px|2 samples of elemental silicon, image provided by '''woelen'''.]]
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{{Infobox element
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'''Silicon''' is a metalloid [[element]] with the atomic number 14 and the chemical symbol '''Si'''. It is an extremely common element, but it is difficult to get ahold of it. However, due to its numerous semiconductor applications, it is relatively easy to get silicon at extremely high purities, such as 99.9999%.
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<!-- top -->
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|image name=Silicon by woelen.jpg
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|image alt=
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|image size=320
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|image name comment=2 samples of elemental silicon, image provided by woelen.
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|image name 2=
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|image alt 2=
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|image size 2=
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|image name 2 comment=
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<!-- General properties -->
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|name=Silicon
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|symbol=Si
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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=Lustrous black solid, with bluish cast
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<!-- Periodic table -->
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|above=[[Carbon|C]]
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|below=[[Germanium|Ge]]
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|left=[[Aluminium]]
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|right=[[Phosphorus]]
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|number=14
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|atomic mass=28.085
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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=
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|period=3
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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=[Ne] 3s<sup>2</sup> 3p<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, 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 black
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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=1687
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|melting point C=1414
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|melting point F=​2577
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|melting point ref=
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|melting point comment=
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|boiling point K=3538
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|boiling point C=3265
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|boiling point F=5909
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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=2.329
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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 2 ref=
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|density gpcm3nrt 2 comment=
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|density gpcm3nrt 3=
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|density gpcm3nrt 3 ref=
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|density gpcm3nrt 3 comment=
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|density gpcm3mp=2.57
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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=50.21
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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=383
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|heat vaporization ref=
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|heat vaporization comment=
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|heat capacity=19.789
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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=1908
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|vapor pressure 10=2102
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|vapor pressure 100=2339
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|vapor pressure 1 k=2636
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|vapor pressure 10 k=3021
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|vapor pressure 100 k=3537
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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 −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=1.90
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|electronegativity ref=
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|electronegativity comment=
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|ionization energy 1=786.5
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|ionization energy 1 ref=
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|ionization energy 1 comment=
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|ionization energy 2=1577.1
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|ionization energy 2 ref=
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|ionization energy 2 comment=
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|ionization energy 3=3231.6
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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=111
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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=111
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|covalent radius ref=
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|covalent radius comment=
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|Van der Waals radius=210
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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=8433
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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=2.6
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|thermal expansion at 25 ref=
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|thermal expansion at 25 comment=
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|thermal conductivity=149
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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=
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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=
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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=2.3×10<sup>3</sup>
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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=Diamagnetic
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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=130–188
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|Young's modulus ref=
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|Young's modulus comment=
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|Shear modulus=51–80
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|Shear modulus ref=
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|Shear modulus comment=
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|Bulk modulus=97.6
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|Bulk modulus ref=
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|Bulk modulus comment=
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|Poisson ratio=0.064–0.28
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|Poisson ratio ref=
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|Poisson ratio comment=
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|Mohs hardness=6.5
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|Mohs hardness ref=
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|Mohs hardness comment=
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|Mohs hardness 2=
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|Mohs hardness 2 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=
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|Brinell hardness ref=
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|Brinell hardness comment=
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|CAS number= 7440-21-3
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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 Latin 'silex' or 'silicis', meaning flint
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|predicted by=Antoine Lavoisier
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|prediction date ref=
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|prediction date=1787
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|discovered by=
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|discovery date ref=
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|discovery date=
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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=Jöns Jacob Berzelius (1823)
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|named by= Thomas Thomson
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|named date ref=
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|named date=1817
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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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'''Silicon''' is a metalloid [[chemical element|element]] with the atomic number 14 and the chemical symbol '''Si'''. It is an extremely common element, but it is difficult to get ahold of it. However, due to its numerous semiconductor applications, it is relatively easy to get silicon at extremely high purities, such as 99.9999%.
  
 
==Properties==
 
==Properties==
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===Chemical properties===
 
===Chemical properties===
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Silicon is highly resistant to all acids, but dissolves readily in strong bases. [[Sodium hydroxide]] produces [[sodium silicate]] and [[hydrogen gas]] when reacted with silicon. A large part of silicon's chemical resistance comes from the formation of a [[passivation]] layer of [[silicon dioxide]].
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Silicon is highly resistant to all acids, but dissolves readily in strong bases. [[Sodium hydroxide]] produces [[sodium silicate]] and [[hydrogen]] gas when reacted with silicon. A large part of silicon's chemical resistance comes from the formation of a [[passivation]] layer of [[silicon dioxide]].
  
 
==Availability==
 
==Availability==
−
Silicon can be obtained from the [http://en.wikipedia.org/wiki/Die_%28integrated_circuit%29 dies] found in microprocessors and transistors (the late models, earlier and first generation usually had either [[germanium]] or germanium-silicon). It is fragile, it will shatter if you try to cut it. A better way to separate the silicon is to heat the device, eventually it will fall of. Another source are discarded silicon solar panels.
+
Silicon can be easily obtained from the [http://en.wikipedia.org/wiki/Die_%28integrated_circuit%29 dies] found on many electronic devices, such as microprocessors and transistors (the late models, earlier and first generation usually had either [[germanium]] or germanium-silicon). Sometimes it can also be found on other devices, such as hard drive readers, and alone on electronic boards. Silicon dies are extremely fragile, and will shatter if you try to cut the, also being prone to chipping. A better way to separate the silicon die is to heat the device it's glued to, either with a flame or a heat gun, which will cause the die to fall off. CPU dies are generally covered in a multicolored protection layer, which requires removal, to increase the purity of the silicon.
 +
 
 +
Another source for elemental silicon are discarded silicon solar panels.
  
 
Larger quantities of very pure silicon can be bought from websites such as [http://www.mcssl.com/store/gallium-source/030---silicon-metal GalliumSource], 40$/30-35 g.
 
Larger quantities of very pure silicon can be bought from websites such as [http://www.mcssl.com/store/gallium-source/030---silicon-metal GalliumSource], 40$/30-35 g.
  
 
==Preparation==
 
==Preparation==
−
An easy means of obtaining relatively pure elemental silicon in a home setting is by composing a [[thermite]] mixture of finely powdered [[silicon dioxide]] and aluminum, which can be initiated with a high temperature ignition source, often in the form of [[magnesium]] ribbon. Because this reaction is not particularly vigorous and therefore not self-sustaining, those that use this method of silicon extraction often add an additional component to the mixture to raise the temperature and prevent the reaction from stopping. For example, rather than a stoichiometric ratio of aluminum powder and silicon dioxide, a mixture of 9 parts silicon dioxide, 10 parts aluminum, and 12 parts [[sulfur]] by mass<ref>As used by ''mrhomescientist'' in this video: https://www.youtube.com/watch?v=73YmP_JSrlU</ref>, can be used. Another method to sustain the reaction is through the addition of an [[Oxidizing agent|oxidiser]] (e.g. [[sodium nitrate]]<ref>As tested by No Tears Only Dreams Now.</ref>), though this will likely lower the yield by removing available aluminum. The resultant slag mixture from the thermite reaction can be broken up to reveal pieces of elemental silicon, which can be cleaned by a short immersion in [[hydrochloric acid]]. Caution must be taken in this step, as any [[aluminum sulfide]] produced earlier will react to form [[hydrogen sulfide]], a dangerous and very potent-smelling gas which has effects similar to that of cyanide.
+
An easy means of obtaining relatively pure elemental silicon in a home setting is by composing a [[thermite]] mixture of finely powdered [[silicon dioxide]] and [[aluminium]], which can be initiated with a high temperature ignition source, often in the form of [[magnesium]] ribbon.
 +
 
 +
: x Al + y SiO<sub>2</sub> → Al<sub>2</sub>O<sub>3</sub> + Si + Al<sub>x</sub>Si<sub>y</sub>
 +
 
 +
Because this reaction is not particularly vigorous and therefore not self-sustaining, those that use this method of silicon extraction often add an additional component to the mixture to raise the temperature and prevent the reaction from stopping. For example, rather than a stoichiometric ratio of aluminum powder and silicon dioxide, a mixture of 9 parts silicon dioxide, 10 parts aluminum, and 12 parts [[sulfur]] by mass<ref>As used by ''mrhomescientist'' in this video: https://www.youtube.com/watch?v=73YmP_JSrlU</ref>, can be used. Another method to sustain the reaction is through the addition of an [[Oxidizing agent|oxidizer]] (e.g. [[sodium nitrate]]<ref>As tested by No Tears Only Dreams Now.</ref>), though this will likely lower the yield by removing available aluminum. The resultant slag mixture from the thermite reaction can be broken up to reveal pieces of elemental silicon, which can be cleaned by a short immersion in [[hydrochloric acid]]. Caution must be taken in this step, as any [[aluminium sulfide]] produced earlier will react to form [[hydrogen sulfide]], a dangerous and very potent-smelling gas which has effects similar to that of cyanide.
  
 
==Projects==
 
==Projects==
−
*Silicides
+
*Make silicides
−
*Tribromosilane
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*Make halosilanes
 
*[[Silane]] synthesis (dangerous!)
 
*[[Silane]] synthesis (dangerous!)
 
*Silicon alkoxides
 
*Silicon alkoxides
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<references/>
 
<references/>
 
===Relevant Sciencemadness threads===
 
===Relevant Sciencemadness threads===
 +
*[http://www.sciencemadness.org/talk/viewthread.php?tid=13515 How to make Silicon]
 +
*[http://www.sciencemadness.org/talk/viewthread.php?tid=11798 Silicon electrode for electrolysis]
 +
*[http://www.sciencemadness.org/talk/viewthread.php?tid=2030 Silicon (and Boron)]
  
 
[[Category:Elements]]
 
[[Category:Elements]]
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[[Category:P-block]]
 
[[Category:P-block]]
 
[[Category:Reducing agents]]
 
[[Category:Reducing agents]]
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[[Category:Materials unstable in basic solution]]
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[[Category:Solids]]

Latest revision as of 20:35, 22 July 2023

Silicon,  14Si
Silicon by woelen.jpg
2 samples of elemental silicon, image provided by woelen.
General properties
Name, symbol Silicon, Si
Appearance Lustrous black solid, with bluish cast
Silicon in the periodic table
C
↑
Si
↓
Ge
Aluminium ← Silicon → Phosphorus
Atomic number 14
Standard atomic weight (Ar) 28.085
Group, block , p-block
Period period 3
Electron configuration [Ne] 3s2 3p2
per shell
 2, 8, 4
Physical properties
Lustrous black
Phase Solid
Melting point 1687 K ​(1414 °C, ​​2577 °F)
Boiling point 3538 K ​(3265 °C, ​5909 °F)
Density near r.t. 2.329 g/cm3
when liquid, at  2.57 g/cm3
Heat of fusion 50.21 kJ/mol
Heat of 383 kJ/mol
Molar heat capacity 19.789 J/(mol·K)
 pressure
Atomic properties
Oxidation states 4, 3, 2, 1 −1, −2, −3, −4 ​(an amphoteric oxide)
Electronegativity Pauling scale: 1.90
energies 1st: 786.5 kJ/mol
2nd: 1577.1 kJ/mol
3rd: 3231.6 kJ/mol
Atomic radius empirical: 111 pm
Covalent radius 111 pm
Van der Waals radius 210 pm
Miscellanea
Crystal structure ​Face-centered diamond-cubic
Speed of sound thin rod 8433 m/s (at 20 °C)
Thermal expansion 2.6 µm/(m·K) (at 25 °C)
Thermal conductivity 149 W/(m·K)
Electrical resistivity 2.3×103 Ω·m (at 20 °C)
Magnetic ordering Diamagnetic
Young's modulus 130–188 GPa
Shear modulus 51–80 GPa
Bulk modulus 97.6 GPa
Poisson ratio 0.064–0.28
Mohs hardness 6.5
CAS Registry Number 7440-21-3
History
Naming After Latin 'silex' or 'silicis', meaning flint
Prediction Antoine Lavoisier (1787)
Discovery and first isolation Jöns Jacob Berzelius (1823)
Named by Thomas Thomson (1817)
· references

Silicon is a metalloid element with the atomic number 14 and the chemical symbol Si. It is an extremely common element, but it is difficult to get ahold of it. However, due to its numerous semiconductor applications, it is relatively easy to get silicon at extremely high purities, such as 99.9999%.

Properties

Physical properties

Silicon is a grayish metalloid with a slight blue tint. It is exceptionally light, to the point that it is sometimes described as feeling hollow. It is a semiconductor, so electricity will pass through it, albeit with great resistance. It crystallizes in the cubic crystal system, though amorphous forms exist. It is brittle and prone to chipping.

Chemical properties

Silicon is highly resistant to all acids, but dissolves readily in strong bases. Sodium hydroxide produces sodium silicate and hydrogen gas when reacted with silicon. A large part of silicon's chemical resistance comes from the formation of a passivation layer of silicon dioxide.

Availability

Silicon can be easily obtained from the dies found on many electronic devices, such as microprocessors and transistors (the late models, earlier and first generation usually had either germanium or germanium-silicon). Sometimes it can also be found on other devices, such as hard drive readers, and alone on electronic boards. Silicon dies are extremely fragile, and will shatter if you try to cut the, also being prone to chipping. A better way to separate the silicon die is to heat the device it's glued to, either with a flame or a heat gun, which will cause the die to fall off. CPU dies are generally covered in a multicolored protection layer, which requires removal, to increase the purity of the silicon.

Another source for elemental silicon are discarded silicon solar panels.

Larger quantities of very pure silicon can be bought from websites such as GalliumSource, 40$/30-35 g.

Preparation

An easy means of obtaining relatively pure elemental silicon in a home setting is by composing a thermite mixture of finely powdered silicon dioxide and aluminium, which can be initiated with a high temperature ignition source, often in the form of magnesium ribbon.

x Al + y SiO2 → Al2O3 + Si + AlxSiy

Because this reaction is not particularly vigorous and therefore not self-sustaining, those that use this method of silicon extraction often add an additional component to the mixture to raise the temperature and prevent the reaction from stopping. For example, rather than a stoichiometric ratio of aluminum powder and silicon dioxide, a mixture of 9 parts silicon dioxide, 10 parts aluminum, and 12 parts sulfur by mass[1], can be used. Another method to sustain the reaction is through the addition of an oxidizer (e.g. sodium nitrate[2]), though this will likely lower the yield by removing available aluminum. The resultant slag mixture from the thermite reaction can be broken up to reveal pieces of elemental silicon, which can be cleaned by a short immersion in hydrochloric acid. Caution must be taken in this step, as any aluminium sulfide produced earlier will react to form hydrogen sulfide, a dangerous and very potent-smelling gas which has effects similar to that of cyanide.

Projects

  • Make silicides
  • Make halosilanes
  • Silane synthesis (dangerous!)
  • Silicon alkoxides

Handling

Safety

Silicon is nontoxic, as are most of its compounds. Inhaled silicon and silicon dioxide may cause silicosis, however, if inhaled in large quantities.

Storage

No special storage is required. Silicon will slowly form an extremely thin protective oxide layer in open air, however this does not affect its purity significantly.

Disposal

Silicon is non-toxic to the environment. It will slowly oxidize to silicon dioxide in air.

References

  1. ↑ As used by mrhomescientist in this video: https://www.youtube.com/watch?v=73YmP_JSrlU
  2. ↑ As tested by No Tears Only Dreams Now.

Relevant Sciencemadness threads

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