Difference between revisions of "Aluminium"

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[[File:640px-Aluminium-4.jpg|thumb|Aluminum metal sample.]]
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{{Infobox element
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'''Aluminium''' (or '''aluminum''') is a strong and light metal with the symbol '''Al''' and atomic number 13, well known for its high chemical reactivity and its striking reluctance to display it due to its tendency to [[Passivation|passivate]]. It is commonly and easily found in many household items, and is commonly used as a reductor in many syntheses. It is one of the most common components of thermite mixtures.
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<!-- top -->
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|image name= Al.jpg
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|image alt=
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|image size=
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|image name comment= Aluminum metal sample.
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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= Aluminium
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|symbol= Al
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|pronounce=
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|pronounce ref=
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|pronounce comment=
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|pronounce 2=
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|alt name=
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|alt names=
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|allotropes=
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|appearance= Silvery white
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<!-- Periodic table -->
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|above= [[Boron|B]]
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|below= [[Gallium|Ga]]
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|left= [[Magnesium]]
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|right= [[Silicon]]
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|number= 13
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|atomic mass= 26.9815385(7)
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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= 13
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|group ref=
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|group comment= (boron group)
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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>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, 3
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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=933.47
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|melting point C=660.32
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|melting point F=1220.58
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|melting point ref=
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|melting point comment=
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|boiling point K=2743
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|boiling point C=2470
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|boiling point F=4478
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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=2.7
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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=2.375
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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=10.71
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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=284
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|heat vaporization ref=
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|heat vaporization comment=
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|heat capacity=24.2
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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=1482
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|vapor pressure 10=1632
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|vapor pressure 100=1817
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|vapor pressure 1 k=2054
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|vapor pressure 10 k=2364
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|vapor pressure 100 k=2790
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|vapor pressure ref=
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|vapor pressure comment=
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|vapor pressure 1 2=
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|vapor pressure 10 2=
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|vapor pressure 100 2=
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|vapor pressure 1 k 2=
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|vapor pressure 10 k 2=
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|vapor pressure 100 k 2=
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|vapor pressure 2 ref=
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|vapor pressure 2 comment=
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<!-- Atomic properties -->
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|atomic properties comment=
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|oxidation states='''+3''', +2, +1, −1, −2
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|oxidation states ref=
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|oxidation states comment=(an amphoteric oxide)
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|electronegativity=1.61
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|electronegativity ref=
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|electronegativity comment=
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|ionization energy 1=577.5
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|ionization energy 1 ref=
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|ionization energy 1 comment=
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|ionization energy 2=1816.7
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|ionization energy 2 ref=
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|ionization energy 2 comment=
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|ionization energy 3=2744.8
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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=143
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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=121±4
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|covalent radius ref=
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|covalent radius comment=
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|Van der Waals radius=184
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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=face-centered cubic (fcc)
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|crystal structure comment=
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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=
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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.=5,000
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|speed of sound rod at r.t. ref=
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|speed of sound rod at r.t. comment=(rolled)
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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=23.1
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|thermal expansion at 25 ref=
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|thermal expansion at 25 comment=
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|thermal conductivity=237
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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=28.2
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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=70
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|Young's modulus ref=
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|Young's modulus comment=
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|Shear modulus=26
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|Shear modulus ref=
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|Shear modulus comment=
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|Bulk modulus=76
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|Bulk modulus ref=
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|Bulk modulus comment=
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|Poisson ratio=0.35
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|Poisson ratio ref=
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|Poisson ratio comment=
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|Mohs hardness=2.75
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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=160–350
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|Vickers hardness ref=
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|Vickers hardness comment=
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|Brinell hardness=160–550
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|Brinell hardness ref=
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|Brinell hardness comment=
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|CAS number=7429-90-5
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|CAS number ref=
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|CAS number comment=
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<!-- History -->
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|naming=
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|predicted by=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=Hans Christian Ørsted (1825)
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|named by= Humphry Davy
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|named date ref=
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|named date=1807
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|history comment label=
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|history comment=
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<!-- Isotopes -->
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|isotopes=
 +
|isotopes comment=
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|engvar=
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}}
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'''Aluminium''' (or '''aluminum''') is a strong and light metal with the symbol '''Al''' and atomic number 13, well known for its high chemical reactivity and its striking reluctance to display it due to its tendency to [[Passivation|passivate]]. It is commonly and easily found in many household items, and is commonly used as a reductor in many syntheses, being the de facto reducer in thermite mixtures.
  
 
==Properties==
 
==Properties==
 
===Physical===
 
===Physical===
−
Physically, aluminium is a typical metal. It is silver, shiny and a good conductor of heat and electricity. Its melting point is 660 degrees Celsius. This temperature is in the upper range of what is achievable in a home chemistry lab and is the highest melting common metal that an ameatur is easily able to melt and forge.
+
Physically, aluminium is a typical metal. It is silver, shiny and a good conductor of heat and electricity. Its melting point is 660 degrees Celsius. This temperature is in the upper range of what is achievable in a home chemistry lab and is the highest melting common metal that an amateur is easily able to melt and forge.
  
 
===Chemical===
 
===Chemical===
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Aluminium will react with strong acids to form its corresponding salt, except [[nitric acid]], where a [[Passivation|passivation layer]] prevents reaction.
 
Aluminium will react with strong acids to form its corresponding salt, except [[nitric acid]], where a [[Passivation|passivation layer]] prevents reaction.
  
−
Hydroxide solutions and molten alkali hydroxides react violently with the metal, producing the [[aluminate]] ion and [[hydrogen]] gas.
+
Hydroxide solutions and molten alkali hydroxides react violently with the metal, producing the aluminate ion and [[hydrogen]] gas.
  
 
:2 Al + 2 NaOH + 6 H<sub>2</sub>O → 2 NaAl(OH)<sub>4</sub> + 3 H<sub>2</sub>
 
:2 Al + 2 NaOH + 6 H<sub>2</sub>O → 2 NaAl(OH)<sub>4</sub> + 3 H<sub>2</sub>
  
−
Aluminium is also oxidised by the [[tetrachlorocuprate]] ion and strongly acidic solutions containing [[Chloride|chlorides]].
+
Aluminium is also oxidized by the [[tetrachlorocuprate]] ion and strongly acidic solutions containing chlorides.
  
−
Aluminium will react with methanol, forming aluminium methoxide and releasing hydrogen. It will only react with ethanol in the presence of [[iodine]] or [[mercuric chloride]], in dry conditions (see [http://en.wikipedia.org/wiki/Aluminium_triethoxide Aluminium triethoxide] synthesis).
+
Aluminium will react with methanol, forming aluminium methoxide and releasing hydrogen. It will only react with ethanol in the presence of [[iodine]] or [[mercury(II) chloride|mercuric chloride]], in dry conditions (see [http://en.wikipedia.org/wiki/Aluminium_triethoxide Aluminium triethoxide] synthesis).
  
 
==Availability==
 
==Availability==
−
A rather crude form of aluminium suitable for many reactions is found as aluminum foil for kitchen use. It is recommended that the cheapest brand possible is purchased, as it is less likely to be alloyed or mixed with additives, and the metal may need to be degreased with acetone. These are especially important if the metal is being made into aluminum powder.[[File:800px-Aluminumfoil.jpg|thumb|Aluminum foil.]]
+
A rather crude form of aluminium suitable for many reactions is found as aluminum foil for kitchen use. It is recommended that the cheapest brand possible is purchased, as it is less likely to be alloyed or mixed with additives, and the metal may need to be degreased with acetone. These are especially important if the metal is being made into aluminum powder. Certain brands of foil such as Reynolds are typically coated on one side with a plastic, which can be dissolved off by using [[acetone]] or [[xylene]].
  
−
Computer heat sinks are usually composed of aluminium, and are often obtained as a byproduct of [[electronics recycling]]. Other electronic devices that contain aluminium in large amounts are hard drive carcasses, electrolytic capacitors (both the carcass and the inner foil), computer board frames, some transistor heatsinks, etc. Aluminium power cables are also a source of aluminium, although they're not 100% pure aluminium, but rather type 1350 or 1370 alloys. Discarded pieces can sometimes be found around transmission towers. Most of these are slightly impure due to additives in the metal.
+
Computer heat sinks are usually composed of aluminium, and are often obtained as a byproduct of [[electronic recycling]]. Other electronic devices that contain aluminium in large amounts are hard drive carcasses, electrolytic capacitors (both the carcass and the inner foil), computer board frames, some transistor heatsinks, etc. Aluminium power cables are also a source of aluminium, although they're not 100% pure aluminium, but rather type 1350 or 1370 alloys. Discarded pieces can sometimes be found around transmission towers. Most of these are slightly impure due to additives in the metal.
  
 
Aluminium serves many uses, and most construction jobs will use the metal somewhere. If you find a light metal and a magnet does not stick to it, chances are that it is aluminium. However, many lightweight metal objects can also be made out of other special alloys or polymers, so it's better to analyse the metal first. Lightweight metal pencil sharpeners however tend to be made of magnesium (with 3% aluminium) instead of aluminium.
 
Aluminium serves many uses, and most construction jobs will use the metal somewhere. If you find a light metal and a magnet does not stick to it, chances are that it is aluminium. However, many lightweight metal objects can also be made out of other special alloys or polymers, so it's better to analyse the metal first. Lightweight metal pencil sharpeners however tend to be made of magnesium (with 3% aluminium) instead of aluminium.
Line 31: Line 302:
  
 
==Preparation==
 
==Preparation==
−
Preparation of metallic aluminium is not viable in a home setting, as it requires a huge amount of electricity to perform molten electrolysis on [[aluminium oxide]] dissolved in [[sodium aluminium fluoride|cryolite]] (sodium aluminium fluoride) at close to 1000 degrees Celsius. This is ironic, as the Hall–Héroult process was developed by Charles Martin Hall in the woodshed laboratory of his family house, making this one of the most significant discoveries of home chemistry.
+
Preparation of metallic aluminium is not viable in a home setting, as it requires a huge amount of electricity to perform molten electrolysis on [[aluminium oxide]] dissolved in [[Sodium hexafluoroaluminate|cryolite]] (sodium aluminium fluoride) at close to 1000 degrees Celsius. This is ironic, as the Hall–Héroult process was developed by Charles Martin Hall in the woodshed laboratory of his family house, making this one of the most significant discoveries of home chemistry.
  
−
It is possible to produce the metal by reacting anhydrous [[aluminium chloride]] with [[potassium]].
+
It is possible to produce the metal by reacting anhydrous [[aluminium chloride]] with [[potassium]]. This process takes place in inert atmosphere or vacuum.
  
 
Extracting the metal using purely chemical processes is so difficult that 150 years ago it was more expensive than [[gold]]. The capstone of the Washington Monument is made of aluminium which was very expensive at the time and seen as elaborate. Now it is not seen as of an value by the common person.
 
Extracting the metal using purely chemical processes is so difficult that 150 years ago it was more expensive than [[gold]]. The capstone of the Washington Monument is made of aluminium which was very expensive at the time and seen as elaborate. Now it is not seen as of an value by the common person.
 +
 +
Aluminium powder can be made by carefully milling Al foil or granules in a ball mill. This must be done under careful conditions, as the resulting fine powder may ignite if there are sparks forming. Non-steel balls tend to be used as grinding media, like Pb-Sb or alumina balls.
  
 
==Projects==
 
==Projects==
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Stable aluminium compounds, such as oxide or hydroxide, can be disposed of by mixing it with cement or concrete and allowing it to harden, as aluminium is already present in the composition of cement.
 
Stable aluminium compounds, such as oxide or hydroxide, can be disposed of by mixing it with cement or concrete and allowing it to harden, as aluminium is already present in the composition of cement.
 +
 +
==Gallery==
 +
<gallery widths="200" position="center" columns="4" orientation="none">
 +
Aluminium piece.jpg|Aluminium metal
 +
Aluminum foil box roll.jpg|Aluminum foil
 +
</gallery>
 +
  
 
==References==
 
==References==
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===Relevant Sciencemadness threads===
 
===Relevant Sciencemadness threads===
 
*[http://www.sciencemadness.org/talk/viewthread.php?tid=21436 cheapest aluminium metal sources?]
 
*[http://www.sciencemadness.org/talk/viewthread.php?tid=21436 cheapest aluminium metal sources?]
 +
 
[[Category:Elements]]
 
[[Category:Elements]]
 
[[Category:Metals]]
 
[[Category:Metals]]
−
[[Category:Poor metals]]
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[[Category:Post-transition metals]]
 
[[Category:Reducing agents]]
 
[[Category:Reducing agents]]
 
[[Category:Readily available chemicals]]
 
[[Category:Readily available chemicals]]
 
[[Category:Essential reagents]]
 
[[Category:Essential reagents]]
 
[[Category:Materials unstable in acidic solution]]
 
[[Category:Materials unstable in acidic solution]]
 +
[[Category:Materials unstable in basic solution]]
 
[[Category:P-block]]
 
[[Category:P-block]]
 +
[[Category:Coinage metals]]

Latest revision as of 11:52, 25 June 2023

Aluminium,  13Al
Al.jpg
Aluminum metal sample.
General properties
Name, symbol Aluminium, Al
Appearance Silvery white
Aluminium in the periodic table
B
↑
Al
↓
Ga
Magnesium ← Aluminium → Silicon
Atomic number 13
Standard atomic weight (Ar) 26.9815385(7)
Group, block (boron group); p-block
Period period 3
Electron configuration [Ne] 3s2 3p1
per shell
 2, 8, 3
Physical properties
Silvery-white
Phase Solid
Melting point 933.47 K ​(660.32 °C, ​1220.58 °F)
Boiling point 2743 K ​(2470 °C, ​4478 °F)
Density near r.t. 2.7 g/cm3
when liquid, at  2.375 g/cm3
Heat of fusion 10.71 kJ/mol
Heat of 284 kJ/mol
Molar heat capacity 24.2 J/(mol·K)
 pressure
Atomic properties
Oxidation states +3, +2, +1, −1, −2 ​(an amphoteric oxide)
Electronegativity Pauling scale: 1.61
energies 1st: 577.5 kJ/mol
2nd: 1816.7 kJ/mol
3rd: 2744.8 kJ/mol
Atomic radius empirical: 143 pm
Covalent radius 121±4 pm
Van der Waals radius 184 pm
Miscellanea
Speed of sound thin rod 5,000 m/s (at ) (rolled)
Thermal expansion 23.1 µm/(m·K) (at 25 °C)
Thermal conductivity 237 W/(m·K)
Electrical resistivity 28.2 Ω·m (at 20 °C)
Magnetic ordering Paramagnetic
Young's modulus 70 GPa
Shear modulus 26 GPa
Bulk modulus 76 GPa
Poisson ratio 0.35
Mohs hardness 2.75
Vickers hardness 160–350 MPa
Brinell hardness 160–550 MPa
CAS Registry Number 7429-90-5
History
Prediction Antoine Lavoisier (1787)
Discovery and first isolation Hans Christian Ørsted (1825)
Named by Humphry Davy (1807)
· references

Aluminium (or aluminum) is a strong and light metal with the symbol Al and atomic number 13, well known for its high chemical reactivity and its striking reluctance to display it due to its tendency to passivate. It is commonly and easily found in many household items, and is commonly used as a reductor in many syntheses, being the de facto reducer in thermite mixtures.

Properties

Physical

Physically, aluminium is a typical metal. It is silver, shiny and a good conductor of heat and electricity. Its melting point is 660 degrees Celsius. This temperature is in the upper range of what is achievable in a home chemistry lab and is the highest melting common metal that an amateur is easily able to melt and forge.

Chemical

Aluminium forms a transparent passivating layer of aluminium oxide upon contact with air. This layer may be removed by simply scratching the surface, or the formation of the layer can be prevented by adding molten gallium metal. With the layer removed, aluminium's strong reducing properties become apparent.

Aluminium will react with strong acids to form its corresponding salt, except nitric acid, where a passivation layer prevents reaction.

Hydroxide solutions and molten alkali hydroxides react violently with the metal, producing the aluminate ion and hydrogen gas.

2 Al + 2 NaOH + 6 H2O → 2 NaAl(OH)4 + 3 H2

Aluminium is also oxidized by the tetrachlorocuprate ion and strongly acidic solutions containing chlorides.

Aluminium will react with methanol, forming aluminium methoxide and releasing hydrogen. It will only react with ethanol in the presence of iodine or mercuric chloride, in dry conditions (see Aluminium triethoxide synthesis).

Availability

A rather crude form of aluminium suitable for many reactions is found as aluminum foil for kitchen use. It is recommended that the cheapest brand possible is purchased, as it is less likely to be alloyed or mixed with additives, and the metal may need to be degreased with acetone. These are especially important if the metal is being made into aluminum powder. Certain brands of foil such as Reynolds are typically coated on one side with a plastic, which can be dissolved off by using acetone or xylene.

Computer heat sinks are usually composed of aluminium, and are often obtained as a byproduct of electronic recycling. Other electronic devices that contain aluminium in large amounts are hard drive carcasses, electrolytic capacitors (both the carcass and the inner foil), computer board frames, some transistor heatsinks, etc. Aluminium power cables are also a source of aluminium, although they're not 100% pure aluminium, but rather type 1350 or 1370 alloys. Discarded pieces can sometimes be found around transmission towers. Most of these are slightly impure due to additives in the metal.

Aluminium serves many uses, and most construction jobs will use the metal somewhere. If you find a light metal and a magnet does not stick to it, chances are that it is aluminium. However, many lightweight metal objects can also be made out of other special alloys or polymers, so it's better to analyse the metal first. Lightweight metal pencil sharpeners however tend to be made of magnesium (with 3% aluminium) instead of aluminium.

Soft drink cans are also a source (although in some countries steel drink cans are also available) and are a popular option when melting down the metal to form ingots or similar. These cans may contain a few percent manganese.

Aluminium powder can be found at hardware stores as aluminium paint, mixed with an organic solvent, usually toluene. A special form of aluminium powder, called German Dark Aluminium, can be purchased online or prepared at home. This type of aluminium powder is mixed with charcoal dust to prevent the oxidation of aluminium particles. Because of this and the fact that is granules are smaller, it is very reactive.

Preparation

Preparation of metallic aluminium is not viable in a home setting, as it requires a huge amount of electricity to perform molten electrolysis on aluminium oxide dissolved in cryolite (sodium aluminium fluoride) at close to 1000 degrees Celsius. This is ironic, as the Hall–Héroult process was developed by Charles Martin Hall in the woodshed laboratory of his family house, making this one of the most significant discoveries of home chemistry.

It is possible to produce the metal by reacting anhydrous aluminium chloride with potassium. This process takes place in inert atmosphere or vacuum.

Extracting the metal using purely chemical processes is so difficult that 150 years ago it was more expensive than gold. The capstone of the Washington Monument is made of aluminium which was very expensive at the time and seen as elaborate. Now it is not seen as of an value by the common person.

Aluminium powder can be made by carefully milling Al foil or granules in a ball mill. This must be done under careful conditions, as the resulting fine powder may ignite if there are sparks forming. Non-steel balls tend to be used as grinding media, like Pb-Sb or alumina balls.

Projects

Handling

Safety

Aluminum is one of the more reactive metals encountered in everyday life, so some special considerations should be taken. Powdered aluminum, especially dark aluminum powder' (named this way because it has some carbon added), is pyrophoric and very reactive in the presence of oxidizers. It may also react violently with water in this form. Aluminum reacts more readily with acids and bases than other metals, as well as solutions of less-reactive metal ions, such as copper. Plan accordingly on what types of solutions and chemicals will come into contact with apparatus or containers made of aluminum.

Aluminium does not play any biological role in the human body. It may, however, increase one's susceptibility to Alzheimer's disease, but the link is tedious at best.

Storage

Aluminium should be stored away from many chemicals, such as strong reducing acids, alkali, halogens, methanol. It should also be kept away from contact with mercury and (liquid) gallium, as these metals will form an amalgam with aluminium and induce structural failure in aluminium made objects. Salts of metals on the lower reactivity series (such as copper(II) sulfate) should not be stored in aluminium containers, as aluminium will act as a reducing agent, especially if they're hygroscopic.

Disposal

Aluminium has negative environmental impacts, due to its high charge to mass ratio interfering with ion exchange systems in waterways and with plants.

Stable aluminium compounds, such as oxide or hydroxide, can be disposed of by mixing it with cement or concrete and allowing it to harden, as aluminium is already present in the composition of cement.

Gallery

  • Aluminium metal

  • Aluminum foil


References

Relevant Sciencemadness threads

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