Difference between revisions of "Sodium"

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(Created page with "'''Sodium''' is an alkali metal with the symbol '''Na''' and the atomic number 11. A highly reactive metal that is less dense than water, it is quite cheap and depending o...")
 
(→‎Reduction with magnesium)
 
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{{Infobox element
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|image name=Sodium by Dnn87.jpg
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|image alt=
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|image size=300
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|image name comment=
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|image name 2=
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|image alt 2=
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<!-- General properties -->
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|name=Sodium
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|symbol=Na
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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=White-silvery metal
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<!-- Periodic table -->
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|above=[[Lithium|Li]]
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|below=[[Potassium|K]]
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|left=[[Neon]]
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|right=[[Magnesium]]
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|number=11
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|atomic mass=22.98976928(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=Alkali metals
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|series ref=
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|series comment=
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|series color=
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|group=1
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|group ref=
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|group comment=I
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|period=3
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|period ref=
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|period comment=
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|block=s
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|block ref=
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|block comment=
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|electron configuration= [Ne] 2s<sup>1</sup>
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|electron configuration ref=
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|electron configuration comment=
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|electrons per shell=2, 8, 1
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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=370.944
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|melting point C=97.794
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|melting point F=​208.029
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|melting point ref=
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|melting point comment=
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|boiling point K=1156.090
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|boiling point C=882.940
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|boiling point F=​1621.292
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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=0.968
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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=0.927
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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=2573
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|critical point MPa=35
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|critical point ref=(extrapolated)
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|critical point comment=
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|heat fusion=2.60
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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=97.42
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|heat vaporization ref=
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|heat vaporization comment=
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|heat capacity=28.230
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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=554
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|vapor pressure 10=617
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|vapor pressure 100=697
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|vapor pressure 1 k=802
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|vapor pressure 10 k=946
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|vapor pressure 100 k=1153
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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='''+1''', −1 ​(a strongly basic oxide)
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|oxidation states ref=
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|oxidation states comment=
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|electronegativity=0.93
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|electronegativity ref=
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|electronegativity comment=
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|ionization energy 1=495.8
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|ionization energy 1 ref=
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|ionization energy 1 comment=
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|ionization energy 2=4562
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|ionization energy 2 ref=
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|ionization energy 2 comment=
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|ionization energy 3=6910.3
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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=186
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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=166±9
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|covalent radius ref=
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|covalent radius comment=
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|Van der Waals radius=227
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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= ​body-centered cubic (bcc)
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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=3200
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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=71
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|thermal expansion at 25 ref=
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|thermal expansion at 25 comment=
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|thermal conductivity=142
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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=47.7
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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=10
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|Young's modulus ref=
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|Young's modulus comment=
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|Shear modulus=3.3
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|Shear modulus ref=
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|Shear modulus comment=
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|Bulk modulus=6.3
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|Bulk modulus ref=
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|Bulk modulus comment=
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|Poisson ratio=
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|Poisson ratio ref=
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|Poisson ratio comment=
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|Mohs hardness=0.5
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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=0.69
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|Brinell hardness ref=
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|Brinell hardness comment=
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|CAS number=7440-23-5
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|CAS number ref=
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|CAS number comment=
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<!-- History -->
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|predicted by=
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|first isolation by=
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|first isolation date=
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|discovery and first isolation by=Humphry Davy (1807)
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|named by=
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|named date ref=
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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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}}
 
'''Sodium''' is an [[alkali metal]] with the symbol '''Na''' and the atomic number 11. A highly reactive metal that is less dense than water, it is quite cheap and depending on the location, easily available. It's not a chemical for beginners, but can have a plethora of uses in the intermediate and advanced chemists' labs.
 
'''Sodium''' is an [[alkali metal]] with the symbol '''Na''' and the atomic number 11. A highly reactive metal that is less dense than water, it is quite cheap and depending on the location, easily available. It's not a chemical for beginners, but can have a plethora of uses in the intermediate and advanced chemists' labs.
  
 
==Properties==
 
==Properties==
 
===Chemical===
 
===Chemical===
−
Sodium reacts with water in a well known and well loved reaction. The heat of the reaction causes the sodium to melt, forming spheres of metal that skirt over the surface of the water due to large amounts of [[hydrogen]] produced. The water will turns alkaline with the formation of [[sodium hydroxide]] and the reaction often gets violent enough to ignite the hydrogen and in larger amounts, explode.
+
Sodium reacts with water in a well known and well loved reaction. The heat of the reaction causes the sodium to melt, forming spheres of metal that skirt over the surface of the water due to large amounts of [[hydrogen]] produced. The water turns alkaline with the formation of [[sodium hydroxide]] and the reaction often gets violent enough to ignite the hydrogen and in larger amounts, explode.
  
−
Sodium reacts quickly with air to form sodium oxides and hydroxides and so is often kept under mineral oil or an inert atmosphere, such as [[argon]] or even [[sulfur hexafluoride]].[[File:228592_orig-1-.jpg|thumb|256px|The spectrum of sodium from a sodium lamp, using a CD as a diffraction grating.]]
+
Sodium reacts quickly with air to form sodium oxides and hydroxides and so is often kept under mineral oil or an inert atmosphere, such as [[argon]] or even [[sulfur hexafluoride]].
  
 
Because of its reaction with water, sodium finds a common use in drying some solvents. However, a few solvents react with the metal, such as [[ethanol]], to form [[sodium ethoxide]].  
 
Because of its reaction with water, sodium finds a common use in drying some solvents. However, a few solvents react with the metal, such as [[ethanol]], to form [[sodium ethoxide]].  
  
 
===Physical===
 
===Physical===
 +
[[File:Sodium lamp spectrum CD.jpg|thumb|256px|The spectrum of sodium from a sodium lamp, using a CD as a diffraction grating.]]
 
Sodium is a very soft metal, easily cut with a knife. Its melting point is very low, at 88 degrees Celsius. It is quite ductile as well, taking a surprisingly low amount of force to extrude it (though it is somewhat difficult).
 
Sodium is a very soft metal, easily cut with a knife. Its melting point is very low, at 88 degrees Celsius. It is quite ductile as well, taking a surprisingly low amount of force to extrude it (though it is somewhat difficult).
  
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==Preparation==
 
==Preparation==
−
There are many methods known for producing sodium, many of which seem easy theoretically but pose their own practical challenges. Producing sodium at home on a large scale is generally not feasible due to the conditions under which the reactions must take place, but is a great project and achievement for the experienced amateur.
+
There are many methods known for producing sodium, many of which seem easy theoretically, but pose their own practical challenges. Producing sodium at home on a large scale is generally not feasible due to the conditions under which the reactions must take place, but is a great project and achievement for the experienced amateur chemist.
  
 
===Electrolysis===
 
===Electrolysis===
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Anode:
 
Anode:
−
:2OH<sup>–</sup> → ½O<sub>2</sub> + H<sub>2</sub>O + 2e<sup>–</sup>
+
:2 OH<sup>–</sup> → ½O<sub>2</sub> + H<sub>2</sub>O + 2e<sup>–</sup>
 
Catode:
 
Catode:
−
:2Na<sup>+</sup> + 2e<sup>–</sup> → 2Na
+
:2 Na<sup>+</sup> + 2e<sup>–</sup> → 2Na
  
 
Overall, the reaction is:
 
Overall, the reaction is:
−
:4NaOH → 4Na + H<sub>2</sub> + H<sub>2</sub>O + O<sub>2</sub>
+
:4 NaOH → 4 Na + H<sub>2</sub> + H<sub>2</sub>O + O<sub>2</sub>
  
 
This process has the downsides of using molten NaOH, which is incredibly corrosive. The vapors given off by the electrolysis process aerosolize small amounts of sodium hydroxide, forming a highly dangerous fog. Passing the evacuated gases through a scrubber is a must, as the fog is highly corrosive to the skin, eyes (especially eyes), mucous membranes.
 
This process has the downsides of using molten NaOH, which is incredibly corrosive. The vapors given off by the electrolysis process aerosolize small amounts of sodium hydroxide, forming a highly dangerous fog. Passing the evacuated gases through a scrubber is a must, as the fog is highly corrosive to the skin, eyes (especially eyes), mucous membranes.
  
−
Another process, known as Downs process, involves the electrolysis of a molten mixture of 65/45 [[Sodium chloride|NaCl]]/[[Calcium Chloride|CaCl]], at 660 degrees Celsius. A significant challange involves the prevention of hot molten sodium from catching fire at these temperatures (such as an inert atmosphere), especially on contact with hot [[chlorine]] or air.
+
Another process, known as Downs process, involves the electrolysis of a molten mixture of 65/45 [[Sodium chloride|NaCl]]/[[Calcium chloride|CaCl<sub>2</sub>]], at 660 degrees Celsius. A significant challenge involves the prevention of hot molten sodium from catching fire at these temperatures (such as an inert atmosphere), especially on contact with hot [[chlorine]] or air.
 +
 
 +
An experimental method involves electrolyzing sodium chloride dissolved in inert organic solvents. Solvents such as ethylene carbonate or propylene carbonate can produce sodium, however, the low solubility of sodium in these solvents hinders effective production. For propylene carbonate, a complexing agent such as anhydrous AlCl<sub>3</sub> or anhydrous FeCl<sub>3</sub> can be used to form the complex salt Na[AlCl<sub>4</sub>] and Na[FeCl<sub>4</sub>] respectively.
  
 
===Reduction with magnesium===
 
===Reduction with magnesium===
−
Metallic sodium can be obtained by reducing sodium hydroxide with [[magnesium]] metal, in a thermite like reaction. Because hot sodium will easily catch fire in open air, it's best to do it in an inert container.
+
''See [[Alcohol catalyzed alkali metal production]] and [[Thermochemical dioxane approach]]''
 +
 
 +
Metallic sodium can be obtained by reducing sodium hydroxide with [[magnesium]] metal, in a thermite like reaction. Because hot sodium will easily catch fire in open air, it's best to do it in a low oxygen container or an inert container. After cooling, the sodium, in powdered form becomes very reactive and will rapidly oxidize over several minutes to sodium oxide.
 +
 
 +
NurdRage has developed a variation of the magnesium reduction:
 +
 
 +
First, in a steel can add a mixture of equimolar amount of [[sodium hydroxide]] and [[magnesium]] metal (turnings or powder), ignite it using some sparkler with magnesium ribbon as fuse and cover the can with a heavy object. The thermite-like reaction will produce a sodium-[[magnesium oxide]] slag, which is very reactive and moisture sensitive. After it has cooled, grind the slag to a relative fine powder and dump it in a flask containing some freshly prepared and dried [[1,4-Dioxane|dioxane]] (avoid using old dioxane as it may contain peroxides). Connect the flask to a distillation setup and distill off the dioxane. As the level of dioxane in the flask decreases, sodium metal droplets will begin to appear at the surface of the solution and start to coalesce. As the level of the dioxane further decreases, the sodium droplets will start to coalesce in larger pieces. Heat the flask until all the dioxane has been removed. Now remove the droplets of sodium metal either directly from the flask or just dump the content of the flask in a dish and remove the sodium from the slag this way. The sodium pieces are then added in mineral oil to limit oxidation. To clean the sodium metal, simply heat the mineral oil until the sodium melts and then add a few drops of [[isopropanol]] until all the sodium has coalesced in a single clean droplet. To get more sodium metal from the slag, repeat the process until no more sodium can be obtained. Yield of this process is 41%, though the yield can be improved by doing the reduction in an inert atmosphere.<ref>https://www.youtube.com/watch?v=jCrFFVVcPUI</ref>
 +
 
 +
Another more efficient way isheat sodium hydroxide with magnesium in mineral oil above 200 °C, in the presence of a tertiary or sterically bulk secondary alcohols, like [[tert-Butanol|t-butanol]] and [[menthol]]. The yield of this route if done right can be as high as 90-95%, though the process takes hours to completion.
  
 
==Projects==
 
==Projects==
 
*Make NaK (sodium potassium alloy) by fusing the two metals together. NaK containing 40% to 90% potassium by weight is liquid at room temperature. The eutectic mixture consists of 77% potassium and 23% sodium, is liquid from −12.6 to 785 °C, and has a density of 866 kg/m<sup>3</sup> at 21 °C and 855 kg/m<sup>3</sup> at 100 °C, making it less dense than water.<sup>[1]</sup> It is highly reactive with water and is stored under dry nitrogen (or, even better, dry argon) for safety reasons
 
*Make NaK (sodium potassium alloy) by fusing the two metals together. NaK containing 40% to 90% potassium by weight is liquid at room temperature. The eutectic mixture consists of 77% potassium and 23% sodium, is liquid from −12.6 to 785 °C, and has a density of 866 kg/m<sup>3</sup> at 21 °C and 855 kg/m<sup>3</sup> at 100 °C, making it less dense than water.<sup>[1]</sup> It is highly reactive with water and is stored under dry nitrogen (or, even better, dry argon) for safety reasons
 
*Dry aprotic solvents
 
*Dry aprotic solvents
−
*Make sodium ethoxide
+
*Make [[sodium ethoxide]]
 +
*[[Birch reduction]]
  
 
==Handling==
 
==Handling==
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While the sodium ion is non-toxic, the metal itself poses more of a physical danger due to its high reactivity. Sodium has a reputation to explode in water, throwing out fire and corrosive sodium hydroxide solution.
 
While the sodium ion is non-toxic, the metal itself poses more of a physical danger due to its high reactivity. Sodium has a reputation to explode in water, throwing out fire and corrosive sodium hydroxide solution.
  
−
'''Always handle sodium with bare hands if you do not have any tools.''' Counterintuitive as it may seem, it is better to handle sodium bare-handed, as you can tell if your hands are wet, and thus dry them off before handling. If you wear gloves, you will not be able to do this, and will risk burning your hand off. And if you wear gloves when it catches fire, the burns will be more severe, as the gloves will melt and stick on the skin.
+
'''Always handle sodium with tongs or tweezers.''' Counter intuitive as it may seem, it is better not to use gloves directly. If you wear gloves it is very difficult to tell if they are dry, and will risk burning your hand off. And if you wear gloves when it catches fire, the burns will be more severe, as the gloves will melt and stick on the skin.
  
−
Using a metal knife or pliers is the best way to pick sodium up.
+
Using tongs, tweezers, pliers or stabbing the soft metal with a scalpel is the best way to pick sodium up.
  
 
===Storage===
 
===Storage===
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==References==
 
==References==
−
<references /> Tdep - Details off the top of my head. Feel free to argue points with me.
+
<references />
 +
*Tdep - Details off the top of my head. Feel free to argue points with me.
 
===Relevant Sciencemadness threads===
 
===Relevant Sciencemadness threads===
 
*[http://www.sciencemadness.org/talk/viewthread.php?tid=2105 unconventional sodium]
 
*[http://www.sciencemadness.org/talk/viewthread.php?tid=2105 unconventional sodium]
 
*[http://www.sciencemadness.org/talk/viewthread.php?tid=2103 Hot electrochemical sodium]
 
*[http://www.sciencemadness.org/talk/viewthread.php?tid=2103 Hot electrochemical sodium]
 +
 +
[[Category:Elements]]
 +
[[Category:Metals]]
 +
[[Category:Alkali metals]]
 +
[[Category:Reducing agents]]
 +
[[Category:Materials unstable in acidic solution]]
 +
[[Category:Materials that react with water]]
 +
[[Category:Air-sensitive materials]]
 +
[[Category:DEA SS List]]
 +
[[Category:S-block]]

Latest revision as of 18:19, 29 August 2021

Sodium,  11Na
Sodium by Dnn87.jpg
General properties
Name, symbol Sodium, Na
Appearance White-silvery metal
Sodium in the periodic table
Li
↑
Na
↓
K
Neon ← Sodium → Magnesium
Atomic number 11
Standard atomic weight (Ar) 22.98976928(2)
Group, block I; s-block
Period period 3
Electron configuration [Ne] 2s1
per shell
 2, 8, 1
Physical properties
Silvery-white
Phase Solid
Melting point 370.944 K ​(97.794 °C, ​​208.029 °F)
Boiling point 1156.090 K ​(882.940 °C, ​​1621.292 °F)
Density near r.t. 0.968 g/cm3
when liquid, at  0.927 g/cm3
Critical point 2573 K, 35 MPa(extrapolated)
Heat of fusion 2.60 kJ/mol
Heat of 97.42 kJ/mol
Molar heat capacity 28.230 J/(mol·K)
 pressure
Atomic properties
Oxidation states +1, −1 ​(a strongly basic oxide)
Electronegativity Pauling scale: 0.93
energies 1st: 495.8 kJ/mol
2nd: 4562 kJ/mol
3rd: 6910.3 kJ/mol
Atomic radius empirical: 186 pm
Covalent radius 166±9 pm
Van der Waals radius 227 pm
Miscellanea
Crystal structure ​​body-centered cubic (bcc)
Speed of sound thin rod 3200 m/s (at 20 °C)
Thermal expansion 71 µm/(m·K) (at 25 °C)
Thermal conductivity 142 W/(m·K)
Electrical resistivity 47.7 Ω·m (at 20 °C)
Magnetic ordering paramagnetic
Young's modulus 10 GPa
Shear modulus 3.3 GPa
Bulk modulus 6.3 GPa
Mohs hardness 0.5
Brinell hardness 0.69 MPa
CAS Registry Number 7440-23-5
Discovery and first isolation Humphry Davy (1807)
· references

Sodium is an alkali metal with the symbol Na and the atomic number 11. A highly reactive metal that is less dense than water, it is quite cheap and depending on the location, easily available. It's not a chemical for beginners, but can have a plethora of uses in the intermediate and advanced chemists' labs.

Properties

Chemical

Sodium reacts with water in a well known and well loved reaction. The heat of the reaction causes the sodium to melt, forming spheres of metal that skirt over the surface of the water due to large amounts of hydrogen produced. The water turns alkaline with the formation of sodium hydroxide and the reaction often gets violent enough to ignite the hydrogen and in larger amounts, explode.

Sodium reacts quickly with air to form sodium oxides and hydroxides and so is often kept under mineral oil or an inert atmosphere, such as argon or even sulfur hexafluoride.

Because of its reaction with water, sodium finds a common use in drying some solvents. However, a few solvents react with the metal, such as ethanol, to form sodium ethoxide.

Physical

The spectrum of sodium from a sodium lamp, using a CD as a diffraction grating.

Sodium is a very soft metal, easily cut with a knife. Its melting point is very low, at 88 degrees Celsius. It is quite ductile as well, taking a surprisingly low amount of force to extrude it (though it is somewhat difficult).

Availability

While the bulk 'price' of sodium is seen to be low, buying small quantities of the metal is usually quite an expensive process. The difficulty and legality of shipping a reactive metal often significantly adds to its price and many online companies will refuse to ship this overseas.

GalliumSource sells sodium by the kilo.

Australia

In some countries, such as Australia, availability is further limited by laws designed to prevent it being used in the manufacture of illicit drugs. Laws are in place that state one needs to sign an EUD (End user declaration) on buying this chemical which is a confusing, poorly enforced and seemingly outdated law for the internet age. In much the way many 'restricted' chemicals in Australia are treated, it is unsure whether owning sodium metal without an EUD would be illegal.

If anyone from Australia has run into issues, or even managed to get an online supplier to sign an EUD before, a comment here would be much appreciated.

Preparation

There are many methods known for producing sodium, many of which seem easy theoretically, but pose their own practical challenges. Producing sodium at home on a large scale is generally not feasible due to the conditions under which the reactions must take place, but is a great project and achievement for the experienced amateur chemist.

Electrolysis

Molten sodium hydroxide (cheaply available) is electrolyzed in a stainless steel or nickel container, in a process known as Castner process.

Anode:

2 OH– → ½O2 + H2O + 2e–

Catode:

2 Na+ + 2e– → 2Na

Overall, the reaction is:

4 NaOH → 4 Na + H2 + H2O + O2

This process has the downsides of using molten NaOH, which is incredibly corrosive. The vapors given off by the electrolysis process aerosolize small amounts of sodium hydroxide, forming a highly dangerous fog. Passing the evacuated gases through a scrubber is a must, as the fog is highly corrosive to the skin, eyes (especially eyes), mucous membranes.

Another process, known as Downs process, involves the electrolysis of a molten mixture of 65/45 NaCl/CaCl2, at 660 degrees Celsius. A significant challenge involves the prevention of hot molten sodium from catching fire at these temperatures (such as an inert atmosphere), especially on contact with hot chlorine or air.

An experimental method involves electrolyzing sodium chloride dissolved in inert organic solvents. Solvents such as ethylene carbonate or propylene carbonate can produce sodium, however, the low solubility of sodium in these solvents hinders effective production. For propylene carbonate, a complexing agent such as anhydrous AlCl3 or anhydrous FeCl3 can be used to form the complex salt Na[AlCl4] and Na[FeCl4] respectively.

Reduction with magnesium

See Alcohol catalyzed alkali metal production and Thermochemical dioxane approach

Metallic sodium can be obtained by reducing sodium hydroxide with magnesium metal, in a thermite like reaction. Because hot sodium will easily catch fire in open air, it's best to do it in a low oxygen container or an inert container. After cooling, the sodium, in powdered form becomes very reactive and will rapidly oxidize over several minutes to sodium oxide.

NurdRage has developed a variation of the magnesium reduction:

First, in a steel can add a mixture of equimolar amount of sodium hydroxide and magnesium metal (turnings or powder), ignite it using some sparkler with magnesium ribbon as fuse and cover the can with a heavy object. The thermite-like reaction will produce a sodium-magnesium oxide slag, which is very reactive and moisture sensitive. After it has cooled, grind the slag to a relative fine powder and dump it in a flask containing some freshly prepared and dried dioxane (avoid using old dioxane as it may contain peroxides). Connect the flask to a distillation setup and distill off the dioxane. As the level of dioxane in the flask decreases, sodium metal droplets will begin to appear at the surface of the solution and start to coalesce. As the level of the dioxane further decreases, the sodium droplets will start to coalesce in larger pieces. Heat the flask until all the dioxane has been removed. Now remove the droplets of sodium metal either directly from the flask or just dump the content of the flask in a dish and remove the sodium from the slag this way. The sodium pieces are then added in mineral oil to limit oxidation. To clean the sodium metal, simply heat the mineral oil until the sodium melts and then add a few drops of isopropanol until all the sodium has coalesced in a single clean droplet. To get more sodium metal from the slag, repeat the process until no more sodium can be obtained. Yield of this process is 41%, though the yield can be improved by doing the reduction in an inert atmosphere.[1]

Another more efficient way isheat sodium hydroxide with magnesium in mineral oil above 200 °C, in the presence of a tertiary or sterically bulk secondary alcohols, like t-butanol and menthol. The yield of this route if done right can be as high as 90-95%, though the process takes hours to completion.

Projects

  • Make NaK (sodium potassium alloy) by fusing the two metals together. NaK containing 40% to 90% potassium by weight is liquid at room temperature. The eutectic mixture consists of 77% potassium and 23% sodium, is liquid from −12.6 to 785 °C, and has a density of 866 kg/m3 at 21 °C and 855 kg/m3 at 100 °C, making it less dense than water.[1] It is highly reactive with water and is stored under dry nitrogen (or, even better, dry argon) for safety reasons
  • Dry aprotic solvents
  • Make sodium ethoxide
  • Birch reduction

Handling

Safety

While the sodium ion is non-toxic, the metal itself poses more of a physical danger due to its high reactivity. Sodium has a reputation to explode in water, throwing out fire and corrosive sodium hydroxide solution.

Always handle sodium with tongs or tweezers. Counter intuitive as it may seem, it is better not to use gloves directly. If you wear gloves it is very difficult to tell if they are dry, and will risk burning your hand off. And if you wear gloves when it catches fire, the burns will be more severe, as the gloves will melt and stick on the skin.

Using tongs, tweezers, pliers or stabbing the soft metal with a scalpel is the best way to pick sodium up.

Storage

Sodium metal should be stored in closed containers, under mineral oil, or under inert atmosphere, such as argon or sulfur hexafluoride. If stored under oil, it will slowly oxidize, though this depends on the container.

Disposal

Disposal of sodium should be done in a safe area by reacting the metal with anhydrous isopropanol (you can burn or throw the metal in water, but that's significantly more dangerous). Sodium hydroxide can be neutralized with any acid (though acetic acid or citric acid are cheaper).

References

  1. ↑ https://www.youtube.com/watch?v=jCrFFVVcPUI
  • Tdep - Details off the top of my head. Feel free to argue points with me.

Relevant Sciencemadness threads

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